Compositions and methods for the assembly of polynucleotides

ABSTRACT

The present invention provides compositions and methods for rapid assembly of one or more assembled polynucleotides from a plurality of component polynucleotides. The methods of the invention utilize circular nucleic acid vectors that comprise a DNA segment D flanked by an annealable linker sequence, annealable linker sequence pairs LA and LB, or annealable linker sequence/primer binding segment pairs LA and PB or PA and LB. Restriction endonuclease digestion of a plurality of vectors containing the DNA segments to be assembled generates a plurality of DNA fragments comprising the elements PA-D-LB, LA-D-LB, and LA-D-PB or D-LB, LA-D-LB, and LA-D. The sequences of annealable linker sequences LA and LB provide complementary termini to the DNA fragments, which are utilized in host cell mediated homologous recombination or together with primer binding segments PA and PB in a polymerase cycling assembly reaction for the ordered assembly of the various DNA segments into one or more assembled polynucleotides.

This application is a continuation of U.S. application Ser. No.12/622,401, filed on Nov. 19, 2009, which claims benefit under 35 U.S.C.§119(e) of U.S. Provisional Application No. 61/116,109, filed on Nov.19, 2008, and U.S. Provisional Application No. 61/162,230, filed on Mar.20, 2009, the contents of which are hereby incorporated by reference intheir entireties.

1. FIELD OF THE INVENTION

The present invention relates generally to the field of recombinant DNAtechnology and, more particularly, to improved methods for the orderedassembly of a plurality of DNA segments into an assembledpolynucleotide.

2. BACKGROUND OF THE INVENTION

Recombination of polynucleotides can be carried out using many methodsknown in the art. Traditional techniques for recombining nucleic acidshave utilized restriction enzymes and ligating enzymes for the creationof novel nucleic acid molecules. Recombinant molecules such as cloningand expression vectors can be utilized to integrate a nucleic acidsequence of interest into the genome of a host cell, and/or drive theexpression of one or more genes of interest. Utilization of a vector todrive expression of a gene of interest in the cell, for example a yeastcell, requires that the vector contain requisite genetic elements thatenable replication and expression of the gene of interest. Theseelements may include, for example, the gene or genes of interest, apromoter sequence, a terminator sequence, selectable markers,integration loci, and the like.

Assembly of elements into a single vector using traditional restrictionand ligation enzyme-based methods can be time-consuming and laborious.Each sub-cloning step, i.e., the introduction of a new nucleic acidfragment into an existing polynucleotide, can require that the resultingclone be screened and characterized before the introduction ofadditional fragments. Clones produced by blunt end ligation requireconfirmation that the fragment was introduced in the proper orientation.On the other hand, sticky-end ligation requires that the restrictionsites utilized to produce the sticky ends on the acceptor fragment alsobe present in the donor fragment, but not at a site that would interruptthe sequence of interest within the donor fragment. Thus, the selectionof workable restriction sites depends entirely on the compositions ofthe pieces being joined and must be carefully considered in each case.In addition, these methods often introduce extraneous nucleic acidsequences to the resulting clone that can interfere with the structureand function of the desired gene products. Further limiting theefficiency of restriction-enzyme based cloning methods is the intrinsiclimitation on the number of nucleic acid molecules that can be ligatedtogether in a single reaction.

The polymerase chain reaction (PCR) is a powerful technique by whichspecific polynucleotide sequences, including genomic DNA, cDNA and mRNA,are amplified in vitro. PCR typically comprises contacting separatecomplementary strands of a target nucleic acid with two oligonucleotideprimers under conditions that allow for the formation of complementaryprimer extension products on both strands. These strands act astemplates for the synthesis of copies of the desired nucleic acidsequences. By repeating the separation and synthesis steps in anautomated system, exponential duplication of the target sequences can beachieved.

One method of PCR, termed “splicing by overlap extension” (“SOE”; see,e.g., U.S. Pat. No. 5,023,171), facilitates the assembly of DNAmolecules at precise junctions without the use of restriction enzymes orligase. Component fragments to be recombined are generated in separatepolymerase chain reactions using uniquely designed primers which produceamplicons having complementary termini to one another. Upon mixing anddenaturation of these amplicons, strands having complementary sequencesat their 3′ ends overlap and act as primers for each other. Extension ofthis overlap by DNA polymerase produces a nucleic acid molecule in whichthe original sequences are “spliced” together. Subsequent rounds of PCRamplify the resulting spliced polynucleotide.

SOE, while more efficient than traditional ligation enzyme-based methodsfor combining a plurality of nucleic acid fragments, does require timeto optimize primer sequences and amplification conditions to producedesired products. Each junction between the fragments to be splicedtogether must be individually considered, and a pair of primers must bedesigned for each fragment in order to make the ends compatible.Traditional considerations for the design of PCR primers, e.g., meltingtemperature, G-C content, avoidance of hairpin and dimer formation, andstringency for false priming sites, must be considered even morecarefully as the number of fragments to be spliced in the SOE reactionincreases.

Thus, despite advances in recombinant DNA technology, there exists aneed for improved methods that provide for the rapid and orderedassembly of polynucleotides. Particularly needed are methods which canfacilitate the assembly of a number of polynucleotides with minimalmanipulation and characterization of intermediate products, and withoutthe need for primer optimization steps. These and other needs can be metby compositions and methods of the present invention.

3. SUMMARY OF THE INVENTION

The compositions and methods provided herein allow for rapid and orderedassembly, or “stitching,” of component polynucleotides into assembledpolynucleotides. In some embodiments, the methods provided hereinutilize circular nucleic acid assembly vectors. In certain embodiments,an assembly vector comprises a component polynucleotide wherein thecomponent polynucleotide comprises a DNA segment flanked by: (i) anannealable linker on the 3′ end; (ii) a primer binding segment on the 5′end and an annealable linker on the 3′ end; (iii) an annealable linkeron both the 3′ end and on the 5′ end; (vi) an annealable linker on the5′ end and primer binding segment on the 3′ end; or (v) an annealablelinker on the 5′ end.

In some embodiments, a plurality of component polynucleotides can bestitched together by providing a plurality of assembly vectors in asingle reaction vessel. In certain embodiments, componentpolynucleotides can be excised from their assembly vectors within thereaction vessel. In some embodiments, the component polynucleotides canthen be denatured, annealable linker sequences can be annealed tocomplementary strands on an adjacent component polynucleotide, and thecomponent polynucleotides can be stitched together into an assembledpolynucleotide by splicing by overlap extension (SOE) followed by PCR.In other embodiments, component polynucleotides excised from assemblyvectors can be assembled into an assembled polynucleotide in vivo byhomologous recombination within a host cell transformed with thecomponent polynucleotides. Assembled polynucleotides can be furthercombined in vivo by host cell mediated homologous recombination.

The efficiency of polynucleotide assembly can be enhanced by theprovision of a standard set of annealable linker sequences that are usedwithin the assembly vector, for example, those described herein as SEQID NOS: 1 to 23. The annealable linker sequences provide sequenceoverlap between adjacent component polynucleotides in the assemblyreaction. Ideally, the annealable linker sequences lack appreciablesecondary structure both at the RNA and at the DNA level, do not crossreact in an undesirable manner with one another, and have relativelyhigh melting temperatures (T_(m)). Consequently, a number of componentpolynucleotides can be stitched together without the need for designingunique primers for each component polynucleotide, thereby saving timeand labor. Compositions and methods provided herein can be used toassemble many types of polynucleotides, including synthetic genes,constructs, cloning vectors, expression vectors, chromosomes, genomes,peptide libraries, and the like.

In one aspect, provided herein is a vector, i.e., an assembly vector,that can be used in the assembly of one or more assembledpolynucleotides from a plurality of component polynucleotides.

In some embodiments, the assembly vector is a circular polynucleotidethat comprises, in a 5′ to 3′ orientation, a restriction site RA, anannealable linker sequence LA, a DNA segment D, an annealable linkersequence LB, and a restriction site RB (i.e., 5′-RA-LA-D-LB-RB-3′). Insome embodiments, the assembly vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, a DNAsegment D, an annealable linker sequence LB, and a restriction site RB(i.e., 5′-RA-D-LB-RB-3′). In some embodiments, the assembly vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, an annealable linker sequence LA, a DNA segment D,and a restriction site RB (i.e., 5′-RA-LA-D-RB-3′). In some embodiments,the assembly vector is a circular polynucleotide that comprises, in a 5′to 3′ orientation, a restriction site RA, a primer binding segment PA, aDNA segment D, an annealable linker sequence LB, and a restriction siteRB (i.e., 5′-RA-PA-D-LB-RB-3′). In some embodiments, the assembly vectoris a circular polynucleotide that comprises, in a 5′ to 3′ orientation,a restriction site RA, an annealable linker sequence LA, a DNA segmentD, a primer binding segment PB, and a restriction site RB (i.e.,5′-RA-LA-D-PB-RB-3′). In some embodiments, the assembly vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, an annealable linker sequence LA, a DNA segment D,an annealable linker sequence LB, and a restriction site RB (i.e.,5′-RA-LA-D-LB-RB-3′). Exemplary assembly vectors are provided in FIG. 1Band FIG. 2.

In some embodiments, a primer binding segment (i.e., PA or PB) can beany nucleotide sequence that is not complementary with any of theannealable linker sequences that are used to make an assembledpolynucleotide. In some embodiments, a primer binding segment includes arestriction endonuclease recognition site and/or cleavage site. In someembodiments, a primer binding segment comprises a nucleic acid sequenceof one of the available linker sequences (e.g., one of SEQ ID NOS: 1 to23), or complements thereof, not being used in the particular assemblyreaction. In some embodiments, the nucleic acid sequence of primerbinding segment PA is selected from the group consisting of SEQ ID NOS:24, 25, and complements thereof. In some embodiments, the nucleic acidsequence of primer binding segment PB is selected from the groupconsisting of SEQ ID NOS: 24, 25, and complements thereof. In preferableembodiments, primer binding segment PA and primer binding segment PB arenot identical in sequence.

In some embodiments, the two or more annealable linker sequences are atleast 24 nucleotides in length and have a T_(m) of at least 60° C.

In some embodiments, two or more annealable linker sequences have a G-Ccontent of at least 70% and a T_(m) of at least 70° C., and do not formappreciable secondary DNA structures. In some embodiments, the nucleicsequence of annealable linker sequence LA is selected from the groupconsisting of SEQ ID NOS: 1 to 8, and complements thereof. In someembodiments, the nucleic sequence of annealable linker sequence LB isselected from the group consisting of SEQ ID NOS: 1 to 8, andcomplements thereof. In some embodiments, the nucleic sequences ofannealable linker sequence LA and annealable linker sequence LB areselected from the group consisting of SEQ ID NOS: 1 to 8, andcomplements thereof.

In some embodiments, two or more annealable linker sequences have an A-Tcontent of at least 30% and a T_(m) of at least 65° C., and do not formappreciable secondary DNA or RNA structures. In some embodiments, two ormore annealable linker sequences have a low G-C content and a T_(m) ofat least 65° C., and comprise the sequence motif5′-ANNNNNNNNANNNAANTANNTTNANA-3′ (SEQ ID NO: 248), wherein A stands foradenine, N for any nucleotide, and T for thymine. In some embodiments,the nucleic sequence of annealable linker sequence LA is selected fromthe group consisting of SEQ ID NOS: 9 to 23, and complements thereof. Insome embodiments, the nucleic sequence of annealable linker sequence LBis selected from the group consisting of SEQ ID NOS: 9 to 23, andcomplements thereof. In some embodiments, the nucleic sequences ofannealable linker sequence LA and annealable linker sequence LB areselected from the group consisting of SEQ ID NOS: 9 to 23, andcomplements thereof.

The ordered assembly of the plurality of component polynucleotides canbe controlled by the selection of annealable linker sequences that flanka DNA segment within the assembly vector. Accordingly, in someembodiments, to ensure that component polynucleotides can be assembledin an ordered fashion, the sequences of an annealable linkersequence/annealable linker sequence pair within a particular assemblyvector are not complementary. Similarly, in some embodiments, thesequences of a primer binding segment/annealable linker sequence pairwithin a particular assembly vector are not complementary.

In a particular embodiment, restriction sites RA and RB are cleavable bythe same restriction endonuclease so as to facilitate the excision ofthe component polynucleotide from the assembly vector. In someembodiments, restriction site RA or RB is cleavable by a restrictionendonuclease that leaves a 5′ or 3′ overhang. In other embodiments,restriction site RA or RB is cleavable by a restriction endonucleasethat leaves a blunt end. In some embodiments, restriction sites RA andRB are cleavable by the same restriction endonuclease. In still otherembodiments, the restriction sites RA and RB are cleavable by a Type IISrestriction endonuclease. In some embodiments, the restriction sites RAand RB are cleavable by the same Type IIS restriction endonuclease. In aparticular embodiment, restriction sites RA and RB are cleavable by SapIor LguI restriction endonucleases.

In another aspect, the invention provides an entry vector useful in thepreparation of an assembly vector comprising a DNA segment.

In some embodiments, the entry vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, arestriction site RY, a DNA segment D, a restriction site RZ, anannealable linker sequence LB, and a restriction site RB (i.e.,5′-RA-RY-D-RZ-LB-RB-3′). In some embodiments, the entry vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, an annealable linker sequence LA, a restrictionsite RY, a DNA segment D, a restriction site RZ, and a restriction siteRB (i.e., 5′-RA-LA-RY-D-RZ-RB-3′). In some embodiments, the entry vectoris a circular polynucleotide that comprises, in a 5′ to 3′ orientation,a restriction site RA, an annealable linker sequence LA, a restrictionsite RY, a DNA segment D, a restriction site RZ, an annealable linkersequence LB, and a restriction site RB (i.e.,5′-RA-LA-RY-D-RZ-LB-RB-3′). In some embodiments, the entry vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, a primer binding segment PA, a restriction site RY,a DNA segment D, a restriction site RZ, an annealable linker sequenceLB, and a restriction site RB (i.e., 5′-RA-PA-RY-D-RZ-LB-RB-3′). In someembodiments, the entry vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, anannealable linker sequence LA, a restriction site RY, a DNA segment D, arestriction site RZ, a primer binding segment PB, and a restriction siteRB (i.e., 5′-RA-LA-RY-D-RZ-PB-RB-3′). An exemplary entry vector isprovided in FIG. 1A.

Digestion of an entry vector with one or more restriction endonucleasescapable of cleaving RY and RZ can create a linearized vector capable ofacceptance of a DNA segment. The DNA segment can be ligated into RY andRZ sites using standard cloning techniques to generate an assemblyvector of the invention. In some embodiments, restriction sites RY andRZ of the entry vector are cleavable by the same restrictionendonuclease. In some embodiments, restriction sites RY and RZ of theentry vector are cleavable by a Type IIS restriction endonuclease. Insome embodiments, restriction sites RY and RZ of the entry vector arecleavable by the same Type IIS restriction endonuclease. In particularembodiments, the Type IIS restriction endonuclease is SchI or MlyI.

In some embodiments, restriction sites RA and RB of the entry vector arecleavable by the same restriction endonuclease. In some embodiments,restriction sites RA and RB of the entry vector are cleavable by a TypeIIS restriction endonuclease. In some embodiments, restriction sites RAand RB of the entry vector are cleavable by the same Type IISrestriction endonuclease. In particular embodiments, the Type IISrestriction endonuclease is SapI or LguI.

In another aspect, the invention provides an assembly compositioncomprising a plurality of assembly vectors for use in the assembly ofone or more assembled polynucleotides from a plurality of componentpolynucleotides. In some embodiments, the assembly compositioncomprises:

-   -   (a) one or more first nucleic acid molecules, wherein each first        nucleic acid molecule is circular and comprises, in a 5′ to 3′        orientation, a first restriction site RA₀, any DNA segment        selected from the group D₀, an annealable linker sequence LB₀,        and a second restriction site RB₀;    -   (b) one or more intermediate nucleic acid molecules wherein each        intermediate nucleic acid molecule n is circular and comprises,        in a 5′ to 3′ orientation, a first restriction site RA_(n), a        first annealable linker sequence LA_(n), any DNA segment        selected from the group D_(n), a second annealable linker        sequence LB_(n), and a second restriction site RB_(n), and        wherein n represents an integer from one to the number of        intermediate nucleic acid molecules; and    -   (c) one or more last nucleic acid molecules, wherein each last        nucleic acid molecule is circular and comprises, in a 5′ to 3′        orientation, a first restriction site RA_(m), an annealable        linker sequence LA_(m), any DNA segment selected from the group        D_(m), a second restriction site RB_(m) wherein m represents an        integer one greater than the number of intermediate nucleic acid        molecules;

whereupon cleavage of restriction sites RA₀ through RB_(m) anddenaturation of the resulting linear nucleic acid molecules, eachannealable linker sequence LB_((p-1)) is capable of hybridizing to thecomplement of annealable linker sequence LA_(p), wherein n is an integerthat varies from 1 to (m−1), wherein p represents an integer from 1 tom, and wherein each group D₀, . . . D_(n), . . . and D_(m) consists ofone or more DNA segments.

In certain embodiments, one or more first nucleic acid molecules furthercomprises a primer binding segment PA positioned 5′ to the DNA segmentselected from the group D₀. In certain embodiments, one or more lastnucleic acid molecules further comprises a primer binding segment PBpositioned 3′ to the DNA segment selected from the group D_(m).

In certain embodiments, the assembly composition comprises two or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises three or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesfour or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises five or moreintermediate nucleic acid molecules. In certain assembly embodiments,the composition comprises six or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesseven or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises eight or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises nine or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesten or more intermediate nucleic acid molecules. In certain embodiments,the assembly composition comprises fifteen or more intermediate nucleicacid molecules. In certain embodiments, the assembly compositioncomprises twenty or more intermediate nucleic acid molecules.

In certain embodiments, m is equal to 1. In certain embodiments, m isequal to 2. In certain embodiments, m is equal to 3. In certainembodiments, m is equal to 4. In certain embodiments, m is equal to 5.In certain embodiments, m is equal to 6. In certain embodiments, m isequal to 7. In certain embodiments, m is equal to 8. In certainembodiments, m is equal to 9. In certain embodiments, m is equal to 10.In certain embodiments, m is equal to or greater than 10.

In some embodiments, upon cleavage of restriction sites RA₀ throughRB_(m) and denaturation of the resulting linear nucleic acid molecules,each annealable linker sequence LB_((p-1)) is capable of selectivelyhybridizing to the complement of annealable linker sequence LA_(p)compared to the other annealable linker sequences, or their complements,in the assembly composition. In some embodiments, each annealable linkersequence L_((p-1)) is identical in sequence to annealable linkersequence LA_(p).

In a particular embodiment, the restriction sites RA₀ through RB_(m) arecleavable by the same restriction endonuclease so as to facilitateexcision of the component polynucleotides from the assembly vectors. Insome embodiments, the restrictions sites RA₀ through RB_(m) arecleavable by SapI and/or LguI restriction endonucleases.

In another aspect, the invention provides a components compositioncomprising a plurality of linear nucleic acid molecules wherein thelinear nucleic acid molecules can be formed by digesting an assemblycomposition with one or more restriction endonucleases capable ofcleaving restriction sites RA₀ through RB_(m) wherein the assemblycomposition comprises:

-   -   (a) one or more first nucleic acid molecules, wherein each first        nucleic acid molecule is circular and comprises, in a 5′ to 3′        orientation, a first restriction site RA₀, any DNA segment        selected from the group D₀, an annealable linker sequence LB₀,        and a second restriction site RB₀;    -   (b) one or more intermediate nucleic acid molecules wherein each        intermediate nucleic acid molecule n is circular and comprises,        in a 5′ to 3′ orientation, a first restriction site RA_(n), a        first annealable linker sequence LA_(n), any DNA segment        selected from the group D_(n), a second annealable linker        sequence LB_(n), and a second restriction site RB_(n), and        wherein n represents an integer from one to the number of        intermediate nucleic acid molecules; and    -   (c) one or more last nucleic acid molecules, wherein each last        nucleic acid molecule is circular and comprises, in a 5′ to 3′        orientation, a first restriction site RA_(m), an annealable        linker sequence LA_(m), any DNA segment selected from the group        D_(m), a second restriction site RB_(m) wherein m represents an        integer one greater than the number of intermediate nucleic acid        molecules;

whereupon cleavage of restriction sites RA₀ through RB_(m) anddenaturation of the resulting linear nucleic acid molecules, eachannealable linker sequence LB_((p-1)) is capable of hybridizing to thecomplement of annealable linker sequence LA_(p), wherein n is an integerthat varies from 1 to (m−1), wherein p represents an integer from 1 tom, and wherein each group D₀, . . . D_(n), . . . and D_(m) consists ofone or more DNA segments.

In certain embodiments, one or more first nucleic acid molecules furthercomprises a primer binding segment PA positioned 5′ to the DNA segmentselected from the group D₀. In certain embodiments, one or more lastnucleic acid molecules further comprises a primer binding segment PBpositioned 3′ to the DNA segment selected from the group D_(m).

In certain embodiments, the components composition comprises two or moreintermediate nucleic acid molecules. In certain embodiments, thecomponents composition comprises three or more intermediate nucleic acidmolecules. In certain embodiments, the components composition comprisesfour or more intermediate nucleic acid molecules. In certainembodiments, the components composition comprises five or moreintermediate nucleic acid molecules. In certain embodiments, thecomponents composition comprises six or more intermediate nucleic acidmolecules. In certain embodiments, the components composition comprisesseven or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises eight or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises nine or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesten or more intermediate nucleic acid molecules. In certain embodiments,the assembly composition comprises fifteen or more intermediate nucleicacid molecules. In certain embodiments, the assembly compositioncomprises twenty or more intermediate nucleic acid molecules.

In certain embodiments, m is equal to 1. In certain embodiments, m isequal to 2. In certain embodiments, m is equal to 3. In certainembodiments, m is equal to 4. In certain embodiments, m is equal to 5.In certain embodiments, m is equal to 6. In certain embodiments, m isequal to 7. In certain embodiments, m is equal to 8. In certainembodiments, m is equal to 9. In certain embodiments, m is equal to 10.In certain embodiments, m is equal to or greater than 10.

In another aspect, provided herein is a kit useful for assembling aplurality of polynucleotides in accordance with the methods providedherein. In some embodiments, the kit comprises: (a) one or more entryvectors described herein; (b) one or more restriction endonucleasescapable of cleaving restriction sites RA and RB of the entry vectors;and (c) one or more restriction endonucleases capable of cleavingrestriction sites RY and RZ of the entry vectors.

In another aspect, the invention provides a library of nucleic acidmolecules. In some embodiments, a nucleic acid molecule of the librarycomprises a first restriction site RA, a DNA segment D, an annealablelinker sequence LB, and a second restriction site RB. In someembodiments, a nucleic acid molecule of the library comprises a firstrestriction site RA, a primer binding segment PA, a DNA segment D, anannealable linker sequence LB, and a second restriction site RB. In someembodiments, a nucleic acid molecule of the library comprises a firstrestriction site RA, an annealable linker sequence LA, a DNA segment D,an annealable linker sequence LB, and a second restriction site RB. Insome embodiments, a nucleic acid molecule of the library comprises afirst restriction site RA, an annealable linker sequence LA, a DNAsegment D, and a second restriction site RB. In some embodiments, anucleic acid molecule of the library comprises a first restriction siteRA, an annealable linker sequence LA, a DNA segment D, a primer bindingsegment PB, and a second restriction site RB.

In some embodiments, the library comprises at least one of each of thefollowing vectors:

-   -   (a) a vector that consists of a circular polynucleotide that        comprises, in a 5′ to 3′ orientation, a restriction site RA, a        DNA segment D, an annealable linker sequence LB, and a        restriction site RB;    -   (b) a vector that consists of a circular polynucleotide that        comprises, in a 5′ to 3′ orientation, a restriction site RA, an        annealable linker sequence LA, a DNA segment D, an annealable        linker sequence LB, and a restriction site RB; and    -   (c) a vector that consists of a circular polynucleotide that        comprises, in a 5′ to 3′ orientation, a restriction site RA, an        annealable linker sequence LA, a DNA segment D, and a        restriction site RB₀.

In some embodiments, the library comprises at least one of each of thefollowing vectors:

(a) a vector that consists of a circular polynucleotide that comprises,in a 5′ to 3′ orientation, a restriction site RA, a primer bindingsegment PA, a DNA segment D, an annealable linker sequence LB, and arestriction site RB;

(b) a vector that consists of a circular polynucleotide that comprises,in a 5′ to 3′ orientation, a restriction site RA, an annealable linkersequence LA, a DNA segment D, an annealable linker sequence LB, and arestriction site RB; and

(c) a vector that consists of a circular polynucleotide that comprises,in a 5′ to 3′ orientation, a restriction site RA, an annealable linkersequence LA, a DNA segment D, a primer binding segment PB, and arestriction site RB₀.

In some embodiments, the DNA segment D comprises a nucleic sequenceselected from the group consisting of a selectable marker, a promoter,genomic targeting sequence, a nucleic acid sequence encoding an epitopetag, and a nucleic acid sequence encoding a gene of interest, a nucleicacid sequence encoding a termination codon and lacZ.

In some embodiments, the library comprises at least one of each of thefollowing nucleic acid molecules:

-   -   (a) a first nucleic acid molecule wherein the first nucleic acid        molecule is circular and comprises, in a 5′ to 3′ orientation, a        first restriction site RA₀, a DNA segment D₀, an annealable        linker sequence LB₀, and a second restriction site RB₀;    -   (b) an intermediate nucleic acid molecule wherein the        intermediate nucleic acid molecule n is circular and comprises,        in a 5′ to 3′ orientation, a first restriction site RA_(n), a        first annealable linker sequence LA_(n), a DNA segment D_(n), a        second annealable linker sequence LB_(n), and a second        restriction site RB_(n), and wherein n represents an integer        from one to the number of intermediate nucleic acid molecules;        and    -   (c) a last nucleic acid molecule wherein the last nucleic acid        molecule is circular and comprises, in a 5′ to 3′ orientation, a        first restriction site RA_(m), an annealable linker sequence        LA_(m), a DNA segment D_(m), a second restriction site RB_(m)        wherein m represents an integer one greater than the number of        intermediate nucleic acid molecules;        whereupon cleavage of restriction sites RA₀ through RB_(m) and        denaturation of the resulting linear nucleic acid molecules,        each annealable linker sequence LB_((p-1)) is capable of        hybridizing to the complement of annealable linker sequence        LA_(p) wherein p represents the integers from 1 to m. In some        embodiments, a first nucleic acid molecule further comprises a        primer binding segment PA positioned 5′ to the DNA segment        selected from the group D₀. In some embodiments, a last nucleic        acid molecules further comprises a primer binding segment PB        positioned 3′ to the DNA segment selected from the group D_(m).

In certain embodiments, the library comprises two or more intermediatenucleic acid molecules. In certain embodiments, the library comprisesthree or more intermediate nucleic acid molecules. In certainembodiments, the library comprises four or more intermediate nucleicacid molecules. In certain embodiments, the library comprises five ormore intermediate nucleic acid molecules. In certain embodiments, thelibrary comprises six or more intermediate nucleic acid molecules. Incertain embodiments, the library comprises seven or more intermediatenucleic acid molecules. In certain embodiments, the assembly compositioncomprises eight or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises nine or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises ten or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesfifteen or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises twenty or moreintermediate nucleic acid molecules.

In certain embodiments, m is equal to 1. In certain embodiments, m isequal to 2. In certain embodiments, m is equal to 3. In certainembodiments, m is equal to 4. In certain embodiments, m is equal to 5.In certain embodiments, m is equal to 6. In certain embodiments, m isequal to 7. In certain embodiments, m is equal to 8. In certainembodiments, m is equal to 9. In certain embodiments, m is equal to 10.In certain embodiments, m is equal to or greater than 10.

In another aspect, provided herein are methods of assembling one or moreassembled polynucleotides from a plurality of component polynucleotides,comprising the steps of:

-   -   (a) digesting an assembly composition with one or more        restriction endonucleases to generate a components composition,        the assembly composition comprising:        -   (i) one or more first nucleic acid molecules, wherein each            first nucleic acid molecule is circular and comprises, in a            5′ to 3′ orientation, a first restriction site RA₀, any            primer binding segment selected from the group PA, any DNA            segment selected from the group D₀, an annealable linker            sequence LB₀, and a second restriction site RB₀;        -   (ii) one or more intermediate nucleic acid molecules wherein            each intermediate nucleic acid molecule n is circular and            comprises, in a 5′ to 3′ orientation, a first restriction            site RA_(n), a first annealable linker sequence LA_(n), any            DNA segment selected from the group D_(n), a second            annealable linker sequence LB_(n), and a second restriction            site RB_(n), and wherein n represents an integer from one to            the number of intermediate nucleic acid molecules; and        -   (iii) one or more last nucleic acid molecules, wherein each            last nucleic acid molecule is circular and comprises, in a            5′ to 3′ orientation, a first restriction site RA_(m), an            annealable linker sequence LA_(m), a DNA segment selected            from the group D_(m), any primer binding segment selected            from the group PB, a second restriction site RB_(m) wherein            m represents an integer one greater than the number of            intermediate nucleic acid molecules; whereupon cleavage of            restriction sites RA₀ through RB_(m) and denaturation of the            resulting linear nucleic acid molecules, each annealable            linker sequence LB_((p-1)) is capable of hybridizing to the            complement of annealable linker sequence LA_(p), wherein n            is an integer that varies from 1 to (m−1), wherein p            represents an integer from 1 to m, and wherein each group            D₀, . . . D_(n), . . . and D_(m) consists of one or more DNA            segments;    -   wherein the one or more restriction endonucleases are capable of        cleaving the restriction sites RA₀ through RB_(m); and    -   (b) contacting the components composition with DNA polymerase,        deoxyribonucleoside triphosphates and one or more first primers        and one or more second primers, under conditions suitable for        denaturation of the nucleic acid molecules, annealing of        annealable linker sequence LB_((p-1)) to annealable linker        sequence LA_(p), and extension therefrom; wherein each said        first primer is capable of hybridizing to one of said primer        binding segments selected from the group PA and each said second        primer is capable of hybridizing to one of said primer binding        segments selected from the group PB; and subjecting the        components composition to polymerase chain reaction,        wherein a polynucleotide is assembled which comprises, in a 5′        to 3′ orientation, one DNA segment selected from each of the        groups D₀, . . . D_(n), . . . and D_(m). In the method, p        represents the integers from 1 to m.

In certain embodiments, the assembly composition comprises two or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises three or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesfour or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises five or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises six or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesseven or more intermediate nucleic acid molecules. In certainembodiments, the assembly composition comprises eight or moreintermediate nucleic acid molecules. In certain embodiments, theassembly composition comprises nine or more intermediate nucleic acidmolecules. In certain embodiments, the assembly composition comprisesten or more intermediate nucleic acid molecules. In certain embodiments,the assembly composition comprises fifteen or more intermediate nucleicacid molecules. In certain embodiments, the assembly compositioncomprises twenty or more intermediate nucleic acid molecules.

In certain embodiments, m is equal to 1. In certain embodiments, m isequal to 2. In certain embodiments, m is equal to 3. In certainembodiments, m is equal to 4. In certain embodiments, m is equal to 5.In certain embodiments, m is equal to 6. In certain embodiments, m isequal to 7. In certain embodiments, m is equal to 8. In certainembodiments, m is equal to 9. In certain embodiments, m is equal to 10.In certain embodiments, m is equal to or greater than 10.

In some embodiments, the assembly composition comprises one firstnucleic acid molecule and one last nucleic acid molecule. In otherembodiments, the assembly composition comprises more than one firstnucleic acid molecule and more than one last nucleic acid molecule, andthe assembly methods provide for the ordered assembly of multiplecomponent polynucleotides into a plurality of assembled polynucleotidesin a combinatorial fashion. In certain embodiments, the assemblycomposition comprises comprises at least two nucleic acid molecules thatcomprise the same annealable linker sequence LA or LB, or the sameprimer binding segment PA or PB, or the same pair of annealable linkersequences LA and LB, or the same pair of annealable linkersequence/primer binding segment LA and PB, or LB and PA.

In another aspect, provided herein are methods for generating host cellscomprising assembled polynucleotides. In some embodiments, the methodscomprise transforming a host cell with an assembled polynucleotidegenerated by the methods of polynucleotide assembly described herein. Inother embodiments, the methods comprise transforming a host cell with aplurality of assembled polynucleotides generated by the methods ofpolynucleotide assembly described herein. In a particular embodiment,the host cell combines two or more assembled polynucleotides into one ormore combined polynucleotide by homologous recombination. In yet otherembodiments, the methods comprise transforming a host cell with aplurality of component polynucleotides and allowing the host cell togenerate one or more assembled or combined polynucleotides by homologousrecombination.

In another aspect, the present invention provides methods for generatinga plurality of host cells comprising a plurality of assembledpolynucleotides. In some embodiments, the plurality of host cells aregenerated by transforming host cells with a composition comprising aplurality of assembled polynucleotides generated by combinatorialassembly of component polynucleotides. In other embodiments, theplurality of host cells are generated by transforming host cells with acomposition comprising a plurality of assembled polynucleotides of whichat least two assembled polynucleotides comprise non-functional segmentsof a selectable marker that upon host cell mediated homologousrecombination generate a functional selectable marker, and by selectinghost cells comprising a combined polynucleotide. In yet otherembodiments, the plurality of host cells are generated by combinatorialmethods by transforming host cells with a component compositioncomprising multiple component polynucleotides of which at least twocomponent polynucleotides comprise the same annealable linker sequenceLA or LB or the same pair of annealable linker sequences LA and LB, andby selecting host cells comprising an assembled polynucleotide.

In another aspect, provided herein is a polynucleotide having a sequenceselected from the group consisting of SEQ ID NOS: 1 to 25.

In another aspect, provided herein is a polynucleotide comprising one ormore sequences selected from the group consisting of SEQ ID NOS: 1 to25.

4. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A provides a schematic of an entry vector useful for thepreparation of an assembly vector of the invention. The vector containsa restriction site RA₀, a primer binding segment PA or an annealablelinker sequence LA, a restriction site RY, a DNA segment D, arestriction site RZ, a primer binding segment PB or an annealable linkersequence LB, and a restriction site RB.

FIG. 1B provides an exemplary method of preparing an entry vector foracceptance of a DNA segment to form an assembly vector. In theexemplary, RY=RZ=SchI. Digestion with SchI, a Type IIS restrictionendonuclease that is capable of producing blunt ends allows forisolation of the vector with the linker sites open to be fused to theDNA segment (D). Blunt-end ligation of D into the entry vector can beperformed by traditional methods using, e.g., T4 DNA ligase.

FIG. 2 presents a schematic of an assembly composition comprising aplurality of assembly vectors (first, intermediate, and last), eachcomprising a DNA segment of interest (D₀, D_(n), D_(m)). The firstnucleic acid molecule comprises a first restriction site RA₀, a primerbinding segment PA, a DNA segment D₀, an annealable linker sequence LB₀,and a second restriction site RB₀. The one or more intermediate nucleicacid molecules comprise a first restriction site RA_(n), a firstannealable linker sequence LA_(n), a DNA segment D_(n), a secondannealable linker sequence LB_(n), and a second restriction site RB_(n)wherein n represents an integer from one to the number of intermediatenucleic acid molecules; and the last nucleic acid molecule comprises afirst restriction site RA_(m), an annealable linker sequence LA_(m), aDNA segment D_(m), a primer binding segment PB, a second restrictionsite RB_(m) wherein m represents an integer one greater than the numberof intermediate nucleic acid molecules.

FIG. 3 presents an exemplary method of assembling, i.e., “stitching” aassembled polynucleotide from four (4) component polynucleotides.Assembly vectors comprising DNA segments to be assembled are pooled in asingle tube and digested with SapI to release component polynucleotidefragments from the assembly vector backbones. Following heatinactivation of SapI, the component polynucleotide fragments aresubjected to denaturing conditions, followed by annealing conditionssufficient for hybridization of the complementary annealable linkerpairs. Following primer extension in the presence of DNA polymerase anddNTPs, primers complementary to PA and PB are added, followed bytraditional PCR amplification. An assembled polynucleotide comprisingcomponent polynucleotides D₀, D₁, D₂, and D₃ assembled in a 5′ to 3′direction is produced as a result of the assembling reaction.

FIG. 4 shows a map of the pRYSE vector.

FIG. 5 shows assembled polynucleotides obtained by assembling 2 to 4component polynucleotides (Assemblies 1 through 6 in Table 7) usingdifferent methods for removing the SapI restriction endonuclease (columnpurification or heat inactivation), different assembly vector DNAconcentrations (5 ng (low DNA concentration) or 50 ng (high DNAconcentration) of smallest fragment with equal molar concentration ofall other fragments, and different annealing temperatures for PCRamplification (54° C. and 72° C.).

FIG. 6 shows assembled polynucleotides obtained by assembling 6 or 9component polynucleotides (Assemblies 7, and 13 through 16 in Table 7)using different DNA polymerases (Phusion (New England Biolabs, Ipswich,Mass.) and PfuUltraII (Stratagene/Agilent, La Jolla, Calif.)).

FIG. 7 shows a map of the pMULE vector. The pMULE entry vector differsfrom the pRYSE entry vector in that it lacks a primer binding segmentsor annealable linker sequences.

FIG. 8 present an exemplary method of combining assembledpolynucleotides into a combined polynucleotide by host cell mediatedhomologous recombination, and integrating the combined polynucleotideinto a chromosome of the host cell. Assembled polynucleotide A comprisesa DNA segment D_(m1) encoding a first non-functional segment of aselectable marker and a DNA segment D₀₁ encoding an upstream genomictargeting sequence. Assembled polynucleotide B comprises a DNA segmentD_(m2) encoding a second non-functional segment of the selectable markerand a DNA segment D₀₂ encoding a downstream genomic targeting sequence.The host cell recombines assembled polynucleotide A and assembledpolynucleotide B at the region of homology in DNA segments D_(m1) andD_(m2) to form a combined polynucleotide comprising a functionalselectable marker, and uses the genomic targeting sequences encoded byDNA segments D₀₁ and D₀₂ to insert the combined polynucleotide byhomologous recombination into its chromosome.

FIG. 9 presents an exemplary method of generating an assembledpolynucleotide by homologous recombination in a host cell andintegration of the assembled polynucleotide into the chromosome of thehost cell. In the first step, an assembly composition comprisingassembly vectors is digested with a restriction endonuclease, resultingin the excision of component polynucleotides from the assembly vectorbackbones. In the second step, the component polynucleotides areintroduced into a host cell where they are recombined at the regions ofhomology in the annealable linker sequences to form an assembledpolynucleotide, and the assembled polynucleotide is integrated into thechromosome of the host cell.

FIG. 10 presents an exemplary method of assembling a plurality ofassembled polynucleotide from seven (7) component polynucleotides in thesame reaction. Assembly vectors comprising DNA segments to be assembledare pooled in a single tube and digested with SapI to release componentpolynucleotides from the assembly vector backbones. Following heatinactivation of SapI the component polynucleotide fragments aresubjected to denaturing conditions, followed by annealing conditionssufficient for hybridization of the complementary annealable linkerpairs. Following primer extension in the presence of DNA polymerase anddNTPs, primers complementary to PA and PB are added, followed bytraditional PCR amplification. The assembly reaction results in theproduction of an assembled polynucleotide comprising componentpolynucleotides D_(01/02), D_(1/2), D₃, and D_(41/42) assembled in a 5′to 3′ direction.

FIG. 11 presents an exemplary method of generating a plurality of hostcells comprising combinatorially combined polynucleotides. Assembledpolynucleotides A1 and A2, each comprising the same upstream genomictargeting sequence and the same first non-functional portion of aselectable marker, and assembled polynucleotides B1 and B2, eachcomprising the same downstream genomic targeting sequence and the samesecond non-functional portion of a selectable marker, arecombinatorially combined by host cell mediated homologous recombinationto generate four different combined polynucleotides, A1/B1, A1/B2,A2/B1, and A2/B2, each comprising a functional selectable marker, thatcan be inserted into a chromosome to generate four different host cells.

FIG. 12A shows the component polynucleotides used in Example 10 for thehigh-throughput generation of combinatorially assembled polynucleotidesand yeast cells comprising combinatorially assembled and combinedpolynucleotides, and the expected assembled and combinedpolynucleotides. US=upstream genomic targeting sequence, DS=downstreamgenomic targeting sequence, P=various promoter sequences, G=variousprotein coding sequences, URA=5′ segment of selectable marker, RA3=3′segment of selectable marker, PA=primer binding segment PmeI-5′,PB=primer binding segment PmeI-3′, LB₀=annealable linker sequence RYSE2, LA_(n1)=annealable linker sequence RYSE 2, LB_(n1)=annealable linkersequence RYSE 15, LA_(n2)=annealable linker sequence RYSE 3,LB_(n2)=annealable linker sequence RYSE16, LA_(n3)=annealable linkersequence RYSE 15, LB_(n3)=annealable linker sequence RYSE 3,LA_(n4)=annealable linker sequence RYSE 16, LB_(n4)=annealable linkersequence RYSE 4, LA_(m1)=annealable linker sequence RYSE 3,LA_(m2)=annealable linker sequence RYSE 4, LA_(m3)=annealable linkersequence RYSE 3.

FIG. 12B shows exemplary assembled polynucleotides (boxed) generated asdescribed in Example 10 and resolved on a 1% agarose gel.

FIG. 12C shows restriction analysis for exemplary cell colonies obtainedas described in Example 10.

FIG. 13A shows the assembled polynucleotide and componentpolynucleotides used in Example 11, and the expected chromosomal locusobtained upon assembly and chromosomal integration by the host cells.

FIG. 13B shows cPCR analysis results obtained for yeast celltransformants generated in Example 11 that comprise chromosomallyintegrated assembled polynucleotides.

FIG. 14 shows the component polynucleotides used in Example 12 for thehigh-throughput generation of yeast cells comprising chromosomallyintegrated combinatorially assembled and combinatorially combinedpolynucleotides, and the expected combined polynucleotides obtained uponassembly and combination by host cell mediated homologous recombination.US=upstream genomic targeting sequence, DS=downstream genomic targetingsequence, P=various promoter sequences, G=various protein codingsequences, URA=5′ segment of selectable marker, RA3=3′ segment ofselectable marker, PA=primer binding segment PmeI-5′, PB=primer bindingsegment PmeI-3′, LB₀=annealable linker sequence RYSE 2,LA_(n1)=annealable linker sequence RYSE 2, LB_(n1)=annealable linkersequence RYSE 15, LA_(n2)=annealable linker sequence RYSE 3,LB_(n2)=annealable linker sequence RYSE16, LA_(n3)=annealable linkersequence RYSE 15, LB_(n3)=annealable linker sequence RYSE 3,LA_(n4)=annealable linker sequence RYSE 16, LB_(n4)=annealable linkersequence RYSE 4, LA_(m1)=annealable linker sequence RYSE 3,LA_(m2)=annealable linker sequence RYSE 4, LA_(m3)=annealable linkersequence RYSE 3.

5. DETAILED DESCRIPTION OF THE EMBODIMENTS 5.1 Definitions

As used herein, the term “polynucleotide” refers to a polymer composedof nucleotide units as would be understood by one of skill in the art.Preferred nucleotide units include but are not limited to thosecomprising adenine (A), guanine (G), cytosine (C), thymine (T), anduracil (U). Useful modified nucleotide units include but are not limitedto those comprising 4-acetylcytidine, 5-(carboxyhydroxylmethyl)uridine,2-O-methylcytidine, 5-carboxymethylaminomethyl-2-thiouridine,5-carboxymethylamino-methyluridine, dihydrouridine,2-O-methylpseudouridine, 2-O-methylguanosine, inosine,N6-isopentyladenosine, 1-methyladenosine, 1-methylpseudouridine,1-methylguanosine, 1-methylinosine, 2,2-dimethylguanosine,2-methyladenosine, 2-methylguanosine, 3-methylcytidine,5-methylcytidine, N6-methyladenosine, 7-methylguanosine,5-methylaminomethyluridine, 5-methoxyaminomethyl-2-thiouridine,5-methoxyuridine, 5-methoxycarbonylmethyl-2-thiouridine,5-methoxycarbonylmethyluridine, 2-methylthio-N6-isopentyladenosine,uridine-5-oxyacetic acid-methylester, uridine-5-oxyacetic acid,wybutoxosine, wybutosine, pseudouridine, queuosine, 2-thiocytidine,5-methyl-2-thiouridine, 2-thiouridine, 4-thiouridine, 5-methyluridine,2-O-methyl-5-methyluridine, 2-O-methyluridine, and the like.Polynucleotides include naturally occurring nucleic acids, such asdeoxyribonucleic acid (“DNA”) and ribonucleic acid (“RNA”), as well asnucleic acid analogs. Nucleic acid analogs include those that includenon-naturally occurring bases, nucleotides that engage in linkages withother nucleotides other than the naturally occurring phosphodiester bondor that include bases attached through linkages other thanphosphodiester bonds. Thus, nucleotide analogs include, for example andwithout limitation, phosphorothioates, phosphorodithioates,phosphorotriesters, phosphoramidates, boranophosphates,methylphosphonates, chiral-methyl phosphonates, 2-O-methylribonucleotides, peptide-nucleic acids (PNAs), and the like.

As used herein, a “component polynucleotide” refers to a polynucleotidesequence that can be assembled together to form a “assembledpolynucleotide” using the methods of polynucleotide assembly describedherein. When a plurality of assembly vectors are digested with one ormore restriction endonucleases capable of excising the componentpolynucleotides from the assembly vectors, the resulting population ofcomponent polynucleotides can comprise the totality of DNA segments tobe assembled into a assembled polynucleotide.

As used herein, an “assembled polynucleotide” refers to a polynucleotideproduced by the methods of polynucleotide assembly described herein. Theassembled polynucleotide can be comprised of the two or more componentpolynucleotides. In some embodiments, the assembled polynucleotidecomprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or morecomponent polynucleotides. Assembled polynucleotide length can rangefrom about 100 to about 20,000 nucleotides, or more. In someembodiments, the assembled polynucleotide length ranges from about 200to about 10,000, about 200 to about 8000, about 200 to about 5000, about200 to about 3000, or about 200 to about 1000 nucleotides. In otherembodiments, the assembled polynucleotide length can range from about200 to about 2000, about 2000 to about 5000, about 5000 to about 10,000,about 10,000 to about 20,000, or greater than 20,000 nucleotides.

Conventional notation is used herein to describe polynucleotidesequences: the left-hand end of a single-stranded polynucleotidesequence is the 5′-end; the left-hand direction of a double-strandedpolynucleotide sequence is referred to as the 5′-direction.

As used herein, the term “DNA segment,” alternately referred to as“Bits” in the examples below, refers to any isolated or isolatablemolecule of DNA. Useful examples include but are not limited to aprotein-coding sequence, reporter gene, fluorescent marker codingsequence, promoter, enhancer, terminator, intron, exon, poly-A tail,multiple cloning site, nuclear localization signal, mRNA stabilizationsignal, selectable marker, integration loci, epitope tag codingsequence, degradation signal, or any other naturally occurring orsynthetic DNA molecule. In some embodiments, the DNA segment can be ofnatural origin. Alternatively, a DNA segment can be completely ofsynthetic origin, produced in vitro. Furthermore, a DNA segment cancomprise any combination of isolated naturally occurring DNA molecules,or any combination of an isolated naturally occurring DNA molecule and asynthetic DNA molecule. For example, a DNA segment may comprise aheterologous promoter operably linked to a protein coding sequence, aprotein coding sequence linked to a poly-A tail, a protein codingsequence linked in-frame with a epitope tag coding sequence, and thelike.

“Complementary” refers to the topological compatibility or matchingtogether of interacting surfaces of two polynucleotides as understood bythose of skill in the art. Thus, two sequences are “complementary” toone another if they are capable of hybridizing to one another to form astable anti-parallel, double-stranded nucleic acid structure. A firstpolynucleotide is complementary to a second polynucleotide if thenucleotide sequence of the first polynucleotide is substantiallyidentical to the nucleotide sequence of the polynucleotide bindingpartner of the second polynucleotide, or if the first polynucleotide canhybridize to the second polynucleotide under stringent hybridizationconditions. Thus, the polynucleotide whose sequence 5′-TATAC-3′ iscomplementary to a polynucleotide whose sequence is 5′-GTATA-3′.

“Primer” refers to a polynucleotide sequence that is capable ofspecifically hybridizing to a polynucleotide template sequence, e.g., aprimer binding segment, and is capable of providing a point ofinitiation for synthesis of a complementary polynucleotide underconditions suitable for synthesis, i.e., in the presence of nucleotidesand an agent that catalyzes the synthesis reaction (e.g., a DNApolymerase). The primer is complementary to the polynucleotide templatesequence, but it need not be an exact complement of the polynucleotidetemplate sequence. For example, a primer can be at least about 80, 85,90, 95, 96, 97, 98, or 99% identical to the complement of thepolynucleotide template sequence. A primer can be of variable length butgenerally is at least 15 bases. In some embodiments, the primer isbetween 15 and 35 bases long. In some embodiments, the primer is morethan 35 bases long. In other embodiments, the primer has a meltingtemperature (T_(m)), i.e., the temperature at which one half of the DNAduplex will dissociate to become single stranded, of at least 50° C. Inother embodiments, the primer has a T_(m) between about 50° C. and 70°C. In still other embodiments, the primer does not form appreciable DNAor RNA secondary structures so as to not impact the efficiency ofhybridization to the polynucleotide template sequence.

As used herein, the term “primer binding segment” is a polynucleotidesequence that binds to a primer so as to provide a point of initiationfor synthesis of a complementary polynucleotide under conditionssuitable for synthesis. In some embodiments, the primer binding sequenceis one of the annealable linkers of the present invention. A sequence isa primer binding sequence instead of an annealable linker by the absenceof a complementary linker within a given set of assembly vectors orcomponent polynucleotides within an assembly composition. In someembodiments, the primer binding segment can function as a genomictargeting sequence, e.g., an upstream or downstream genomic targetingsequence.

As used herein, the term “linker sequence” and “annealable linkersequence” are used interchangeably and refer to a polynucleotidesequence contained within an entry vector and assembly vector describedherein. In particular, an annealable linker sequence flanks a DNAsegment within an entry vector or assembly vector. Upon excision of acomponent polynucleotide from an assembly vector, and denaturation ofthe component polynucleotide, an annealable linker is capable ofspecifically hybridizing to a complementary annealable linker sequenceof an adjacent component polynucleotide in a polynucleotide assemblyreaction, as described herein. An annealable linker, upon annealing witha complementary linker strand, can provide a point of initiation forsynthesis of a complementary polynucleotide.

As used herein, the term “vector” is used in reference toextrachromosomal nucleic acid molecules capable of replication in a celland to which an insert sequence can be operatively linked so as to bringabout replication of the insert sequence. Useful examples include butare not limited to circular DNA molecules such as plasmid constructs,phage constructs, cosmid vectors, etc., as well as linear nucleic acidconstructs (e.g., lambda phage constructs, bacterial artificialchromosomes (BACs), yeast artificial chromosomes (YACs), etc.). A vectormay include expression signals such as a promoter and/or a terminator, aselectable marker such as a gene conferring resistance to an antibiotic,and one or more restriction sites into which insert sequences can becloned. Vectors can have other unique features (such as the size of DNAinsert they can accommodate).

As used herein, the term “entry vector” refers to a cloning vectorplasmid that can serve as a parental vector for the preparation of anassembly vector to be used in the polynucleotide assembly methodsprovided herein. An entry vector comprises two annealable linkersequences, or an annealable linker sequence and a primer bindingsegment, which flank restriction sites that can be utilized for theintroduction of a DNA segment to form an assembly vector. As usedherein, an “assembly vector” refers to an entry vector to which a DNAsegment has been introduced. An assembly vector can be used in thepolynucleotide assembly methods described herein to provide a componentpolynucleotide to be assembled into a assembled polynucleotide.

As used herein, the term “assembly vector” refers to a vector comprisingone annealable linker sequence, two annealable linker sequences, or anannealable linker sequence and a primer binding segment, and a DNAsegment.

As used herein, the term “restriction enzyme” or “restrictionendonuclease” refers to a member or members of a classification ofcatalytic molecules that bind a cognate sequence of DNA and cleave theDNA molecule at a precise location within that sequence. Restrictionendonucleases include Type IIS restriction endonucleases. This class ofenzymes differs from other restriction endonucleases in that therecognition sequence is separate from the site of cleavage. Someexamples of Type IIS restriction enzymes include AlwI, BsaI, BbsI, BbuI,BsmAI, BsrI, BsmI, BspMI, Earl, Esp3I, FokI, HgaI, HphI, LguI, MboII,Mn1I, PleI, SapI, SchI, SfaNi, and the like. Many of these restrictionendonucleases are available commercially and are well known to thoseskilled in the art.

As used herein, the term “annealable linker sequence duplex” refers toone annealable linker sequence strand aligned with a substantiallycomplementary annealable linker sequence strand in antiparallelassociation. Complementarity need not be perfect; annealable linkersequence duplexes may contain mismatched base pairs or unmatched bases,although in particular embodiments, the annealable linker sequenceduplex comprises two annealable linker sequence strands having perfectcomplementarity.

As used herein, the term “genomic targeting sequence” refers to anucleotide sequence that is present in the genome of a host cell at asite at which a polynucleotide of the invention is to be inserted byhost cell mediated homologous recombination. The terms “upstream genomictargeting sequence” and “downstream genomic targeting sequence” refer togenomic targeting sequences that are located upstream and downstream ofeach other in the genome of a host cell.

As used herein, the term “chromosomal targeting sequence” refers to anucleotide sequence that is present in a chromosome of a host cell at asite at which a polynucleotide of the invention is to be inserted byhost cell mediated homologous recombination. The terms “upstreamchromosomal targeting sequence” and “downstream chromosomal targetingsequence” refer to chromosomal targeting sequences that are locatedupstream and downstream of each other in a chromosome of a host cell.

5.2 Methods of Polynucleotide Assembly

In one aspect, the present invention provides rapid, robust, andhigh-throughput methods for the ordered assembly of a plurality ofcomponent polynucleotides into one or more assembled polynucleotides.The methods of the invention utilize circular nucleic acid vectors,termed assembly vectors, that each comprise a DNA segment, D, flanked byan annealable linker sequence (i.e., LA or LB), a pair of annealablelinker sequences (i.e., LA and LB), or an annealable linker sequence anda primer binding segment (i.e., LA and PB or LB and PA), and a pair ofrestriction sites, RA and RB (FIG. 1B). Restriction endonucleasedigestion of a plurality of assembly vectors at restriction sites RA andRB generates a plurality of component polynucleotides comprising theelements 5′-LA-D-3′, 5′-D-LB-3′, 5′-LA-D-LB-3′, 5′-LA-D-PB-3′, or5′-LB-D-PA-3′ (FIG. 3). In the methods of the invention annealablelinker sequences LA and LB provide the component polynucleotides withcomplementary termini that are utilized in a splice overlap extensionassembly reaction followed by polymerase chain reaction (SOE/PCR) toassemble the component polynucleotides into an assembled polynucleotidewith an ordered sequence.

In particular, the methods can provide for assembly into a singleassembled polynucleotide of a number of functional DNA elements,including but not limited to protein-coding sequences, reporter genes,fluorescent marker coding sequences, promoters, enhancers, terminators,introns, exons, poly-A tails, multiple cloning sites, nuclearlocalization signals, mRNA stabilization signals, selectable markers,integration loci, epitope tag coding sequences, and degradation signals.The methods can be used for the assembly of any type of assembledpolynucleotide, including but not limited to synthetic genes,constructs, cloning vectors, expression vectors, chromosomes, genomicintegration constructs, genomes, and DNA libraries. Furthermore, themethods can be used to assemble DNA segments in a single reactionwithout need for manipulation and characterization of intermediateproducts.

In some embodiments, the methods can also provide for the assembly of anassembled polynucleotide from a plurality of component polynucleotidesnot originating from an assembly vector (i.e., DNA segments obtained bystandard procedures known in the art, such as for example, PCRamplification, chemical synthesis, and the like, that are flanked by oneor two annealable linker sequences, LA and/or LB, or by an annealablelinker sequence and a primer binding segment (i.e., LA and PB or LB andPA). The component polynucleotides not originating from an assemblyvector may be added to the assembly reaction at any stage prior to theSOE/PCR reaction or host cell mediated homologous recombination forassembly into the assembled polynucleotide. Thus, in some embodiments,the assembly methods can be used to assemble: (1) componentpolynucleotides derived from assembly vectors comprising one or twoannealable linker sequences, or an annealable linker sequence and aprimer binding segment, and generated by digestion of the assemblyvectors; (2) vectorless DNA fragments flanked by one or two annealablelinker sequences, or by an annealable linker sequence and a primerbinding segment; and (3) combinations thereof.

In some embodiments, provided herein are methods of assembling aplurality of component polynucleotides into one or more assembledpolynucleotides, comprising the steps of:

-   -   (a) digesting an assembly composition with one or more        restriction endonucleases to generate a components composition,        the assembly composition comprising:        -   (i) one or more first nucleic acid molecules, wherein each            first nucleic acid molecule is circular and comprises, in a            5′ to 3′ orientation, a first restriction site RA₀, any            primer binding segment selected from the group PA, any DNA            segment selected from the group D₀, an annealable linker            sequence LB₀, and a second restriction site RB₀;        -   (ii) one or more intermediate nucleic acid molecules wherein            each intermediate nucleic acid molecule n is circular and            comprises, in a 5′ to 3′ orientation, a first restriction            site RA_(n), a first annealable linker sequence LA_(n), any            DNA segment selected from the group D_(n), a second            annealable linker sequence LB_(n), and a second restriction            site RB_(n), and wherein n represents an integer from one to            the number of intermediate nucleic acid molecules; and        -   (iii) one or more last nucleic acid molecules, wherein each            last nucleic acid molecule is circular and comprises, in a            5′ to 3′ orientation, a first restriction site RA_(m), an            annealable linker sequence LA_(m), a DNA segment selected            from the group D_(m), any primer binding segment selected            from the group PB, a second restriction site RB_(m) wherein            m represents an integer one greater than the number of            intermediate nucleic acid molecules; whereupon cleavage of            restriction sites RA₀ through RB_(m) and denaturation of the            resulting linear nucleic acid molecules, each annealable            linker sequence LB_((p-1)) is capable of hybridizing to the            complement of annealable linker sequence LA_(p), wherein n            is an integer that varies from 1 to (m−1), wherein p            represents an integer from 1 to m, and wherein each group            D₀, . . . D_(n), . . . and D_(m) consists of one or more DNA            segments;    -   wherein the one or more restriction endonucleases are capable of        cleaving the restriction sites RA₀ through RB_(m); and    -   (b) contacting the components composition with DNA polymerase,        deoxyribonucleoside triphosphates and one or more first primers        and one or more second primers, under conditions suitable for        denaturation of the nucleic acid molecules, annealing of        annealable linker sequence LB_((p-1)) to annealable linker        sequence LA_(p), and extension therefrom; wherein each said        first primer is capable of hybridizing to one of said primer        binding segments selected from the group PA and each said second        primer is capable of hybridizing to one of said primer binding        segments selected from the group PB; and subjecting the        components composition to polymerase chain reaction,        wherein a polynucleotide is assembled which comprises, in a 5′        to 3′ orientation, one DNA segment selected from each of the        groups D₀, . . . D_(n), . . . and D_(m). In the method, p        represents the integers from 1 to m.

FIG. 3 depicts one embodiment of the assembly methods of the inventionfor illustrative purposes. In this example, a total of four componentpolynucleotides are assembled to yield an assembled polynucleotide.However, the assembly methods provided herein can be used to assembleany number of component polynucleotides into one or more assembledpolynucleotides. In some embodiments, the methods provided herein resultin the assembly of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, ormore component polynucleotides into one or more assembledpolynucleotides.

In the example illustrated in FIG. 3, the assembly composition fromwhich the assembled polynucleotide is generated comprises four inputassembly vectors, denoted “first,” “intermediate 1 (int₁),”“intermediate 2 (int₂),” and “last.” Each assembly vector comprises aDNA segment flanked either by an annealable linker sequence and a primerbinding segment, or by two annealable linker sequences. Specifically,DNA segment D₀ is flanked by 5′ primer binding segment PA and 3′annealable linker sequence LB₀. DNA segment D₁ is flanked by 5′ and 3′annealable linker sequences LA₁ and LB₁, and DNA segment D₂ is flankedby 5′ and 3′ annealable linker sequences LA₂ and LB₂. DNA segment D₃ isflanked by 3′ primer binding segment PB and 5′ annealable linkersequence LA₃. The 5′-PA-D-LB-3′, 5′-LA-D-LB-3′, or 5′-LA-D-PB-3′elements in the assembly vectors are further flanked by SapI restrictionendonuclease sites.

In the first step of the assembly reaction shown in FIG. 3, the assemblycomposition is digested with SapI, resulting in the excision ofcomponent polynucleotides, comprising the elements 5′-PA-D-LB-3′,5′LA-D-LB-3′, or 5′-LA-D-PB-3′, from the assembly vector backbones intoa components composition. Because Sap I is a Type IIS restrictionendonuclease, its recognition site is distal to its cleavage site, andcleavage occurs outside of its recognition sequence. This property makesType IIS restriction endonucleases particularly useful in the assemblyof a polynucleotide according to the methods provided herein, sincepolynucleotides can be assembled which do not comprise arestriction-site scar, which may otherwise result from cleavage ofrestriction sites RA and RB with a non-Type IIS restrictionendonuclease. Referring to FIG. 2, the Type IIS recognition site is 5′of the corresponding cleavage site for each of RA₀, RA_(n), and RA_(m),and 3′ of its cleavage site RB₀, RA_(n), and RA_(m). Thus, restrictionsites RA₀ through RB_(m) are oriented so that cleavage by one or moreType IIS restriction endonucleases capable of cleaving RA₀ throughRB_(m) results in separation of RA₀ from D₀, LB₀ from RB₀, RA_(n), fromLA_(n), LB_(n) from RB_(n), RA_(m) from LA_(m), and D_(m) from RB_(m),wherein resultant linearized nucleic acid molecules comprising D₀, LB₀,RA_(n), LB_(n), LA_(m) or D_(m) do not comprise any of RA₀ throughRB_(m). As a consequence, the resulting component polynucleotides do notinclude any trace of either the restriction enzyme's recognition orcleavage sites. As a result, the inventive methods of polynucleotideassembly can be used to transform host cells multiple times without theintroduction of sequence repeats which may cause genetic instability.

Subsequently, the restriction endonuclease is optionally inactivated. Ifinactivation is desired, any method known in the art for inactivatingendonuclease enzyme activity may be employed, including column orgel-based purification methods. One convenient method is heatinactivation, e.g., at 65° for 20 minutes, which requires little or nomanipulation of the components composition outside of the reaction tube.

Assembly of the component polynucleotides into an assembledpolynucleotide is enabled by sequence duplexes formed by overlappingstrands of complementary termini among the component polynucleotides.Specifically, the annealable linker sequences are designed such thatannealable linker sequence LB₀ can hybridize to the complement ofannealable linker sequence LA₁, annealable linker sequence LB₁ canhybridize to the complement of annealable linker sequence LA₂, andannealable linker sequence LB₂ can hybridize to the complement ofannealable linker sequence LA₃. Thus, in the second step of the assemblyreaction, the component polynucleotides are subjected to denaturingconditions (e.g., heat) to generate single-stranded componentpolynucleotides, which concomitant with or subsequent to thedenaturation step of the assembly reaction are contacted with athermostable DNA polymerase and deoxyribonucleoside triphosphates.

The thermostable DNA polymerase can be any thermostable DNA polymerasedeemed suitable by those of skill in the art. Thermostable DNApolymerases suitable for use in the present methods include but are notlimited to Thermus thermophilus (Tth) DNA polymerase, Thermus aquaticus(Taq) DNA polymerase, Thermotoga neopolitana (Tne) DNA polymerase,Thermotoga maritima (Tma) DNA polymerase, Therm°C°Ccus litoralis (Tli orVENT™) DNA polymerase, Pyr°C°Ccus furiosus (Pfu or DEEPVENT™) DNApolymerase, Pyr°C°Ccus woosii (Pwo) DNA polymerase, Bacillussterothermophilus (Bst) DNA polymerase, Sulfolobus acid°Caldarius (SAC)DNA polymerase, Thermoplasma acidophilum (Tac) DNA polymerase, Thermusflavus (Tfl/Tub) DNA polymerase, Thermus ruber (Tru) DNA polymerase,Thermus br°Ckianus (DYNAZYME™) DNA polymerase, Methanobacteriumthermoautotrophicum (Mth) DNA polymerase, and mutants, variants, andderivatives thereof. Thermostable DNA polymerases having high fidelity(i.e., proofreading properties) and low error rates are preferred. Incertain embodiments, the DNA polymerase is Phusion™ DNA Polymerase (NewEngland Biolabs, Ipswich, Mass.). In other embodiments, the DNAPolymerase is PfuUltra™ II Fusion DNA Polymerase (Strategene/Agilent, LaJolla, Calif.).

The assembly reaction is then subjected to conditions that allow forstrand elongation from the 3′-hydroxyl portions of the overlappingannealable linker sequences, during which the thermostable DNApolymerase fills in the portion between the overlapping annealablelinker sequences. The assembly reaction is subjected to a limited numberof repeating cycles of denaturation/annealing/extension (e.g., for 5-15cycles) during which a substantial amount of double-stranded assembledpolynucleotides are formed. During this cycling, the componentpolynucleotides act as both primers and template to generate a fulllength template for the assembled polynucleotide. In certainembodiments, the annealing and extension steps of the PCR can both beperformed at 72° C.

In contrast to the annealable linker sequences LA and LB, the primerbinding segments PA and PB are designed to not overlap with each otheror any of the annealable linker sequences or DNA segments, but ratherserve as binding sites for primers used to amplify the full lengthassembled polynucleotide. Thus, in steps 4 and 5 of the assemblyreaction, primers complementary to primer binding segments PA and PB areadded, and the composition is subjected to traditional PCR amplificationconditions. The PCR amplification conditions can be any PCRamplification conditions deemed suitable by those of skill in the art,including those described in PCR Technology: Principles and Applicationsfor DNA Amplification, ed. H A Erlich, Stockton Press, New York, N.Y.(1989); PCR Prot°Cols: A Guide to Methods and Applications, eds. Innis,Gelfland, Snisky, and White, Academic Press, San Diego, Calif. (1990);Mattila et al. (1991)Nucleic Acids Res. 19: 4967; Eckert, K. A. andKunkel, T. A. (1991) PCR Methods and Applications 1: 17; and U.S. Pat.Nos. 4,683,202 and 4,965,188, each of which are incorporated herein byreference. In certain embodiments, the PCR step of the assembly reactioncomprises about 35 cycles of denaturation, annealing, and extension inthe presence of primers complementary to primer binding segments PA andPB. In certain embodiments, the annealing and extension steps of the PCRcan both be performed at 72°. However, one of skill in the art willunderstand that optimal conditions for successful amplification willdepend on the thermostable DNA polymerase and the annealable linkersequences utilized, and these conditions may be adjusted accordingly.

Optionally, the assembled polynucleotide can be purified by anytechnique apparent to one of skill in the art, e.g., gel electrophoresispurification methods and used for a variety of purposes. For example,the assembled polynucleotide can be inserted into an expression vectorbackbone for sequence verification.

5.3 Methods of Generating Host Cells Comprising AssembledPolynucleotides

In another aspect, the present invention provides methods for generatinghost cells comprising assembled polynucleotides. In some embodiments,the assembled polynucleotide is at least 3 kb in size. In otherembodiments, the assembled polynucleotide is at least 5 kb in size. Instill other embodiments, the assembled polynucleotide is at least 6, 7,8, 9, or 10 kb in size. In still other embodiments, the assembledpolynucleotide is greater than 10 kb in size. In still otherembodiments, the assembled polynucleotide is greater than 15 kb in size.In still other embodiments, the assembled polynucleotide is greater than20 kb in size.

In some embodiments, methods are provided that comprise transforming ahost cell with an assembled polynucleotide generated by the methods ofpolynucleotide assembly described herein. The assembled polynucleotidecan be circularized prior to transformation or can be transformed as alinear molecule. The assembled polynucleotide can be maintained in thehost cell as an extrachromosomal polynucleotide. Alternatively, theassembled polynucleotide can be integrated into the genome of the hostcell, e.g., by host cell mediated homologous recombination. To integratean assembled polynucleotide into the genome by homologous recombination,the assembled polynucleotide must comprise at one terminus a nucleicacid sequence comprising an upstream genomic targeting sequence and atthe other terminus a nucleic acid sequence comprising a downstreamgenomic targeting sequence. Accordingly, an assembled polynucleotidethat is to be integrated into a chromosome of a host cell is generatedfrom an assembly composition comprising a first nucleic acid moleculecomprising an upstream chromosomal targeting sequence and a last nucleicacid molecule comprising a downstream chromosomal targeting sequence,each chromosomal targeting sequence being of sufficient length toinitiate homologous recombination by the host cell with its chromosome.

In other embodiments, the methods comprise transforming a host cell witha plurality of assembled polynucleotides generated by the methods ofpolynucleotide assembly described herein. In a particular embodiment,the host cell combines two or more assembled polynucleotides into asingle combined polynucleotide by homologous recombination. Host celltransformants comprising the combined polynucleotides are selected byvirtue of expressing a selectable marker that is generated in theprocess of combining the assembled polynucleotides. The method isparticularly useful for inserting relatively large pieces ofpolynucleotide into a target polynucleotide by homologous recombination.For chromosomal integration to occur, the combined polynucleotide mustcomprise an upstream genomic targeting sequence located 5′ or 3′ of thecoding sequence of the selectable marker and a downstream genomictargeting sequence located 3′ or 5′ of the coding sequence of theselectable marker, respectively. Genomic integration as used hereinincludes chromosomal integration, i.e., integration of a polynucleotideinto a chromosome of a host cell. Suitable chromosomal integration sitesin Saccharomyces cerevisiae include but are not limited to the NDT80,HO, GAL2, and GAL1-GAL10-GAL7 locus. The method can also be useful forgenerating host cells comprising an extrachromosomally maintainedpolynucleotide, e.g., vectors and expression plasmids. The stability ofeither a chromosomally integrated or an extrachromosomally maintainedcombined polynucleotide is increased when the combined polynucleotidedoes not comprise identical annealable linker sequences or DNA segmentsarranged as direct repeats that can otherwise initiate additionalhomologous recombination events resulting in the excision of segments ofthe component polynucleotide. Therefore, in some embodiments, theassembled polynucleotides comprise unique annealable linker sequencesand DNA segments. In other embodiments, the assembled polynucleotidescontain one or more identical annealable linker sequences or DNAsegments that upon combination of the assembled polynucleotides arearranged as inverted repeats in the combined polynucleotide.

The generation of an exemplary combined polynucleotide and integrationof the combined polynucleotide into a chromosome of the host cell byhomologous recombination is illustrated in FIG. 8. Two assembledpolynucleotides A and B are taken up by a host cell that is capable ofhomologous recombination. Each assembled polynucleotide comprises a DNAsegment D_(m) that encodes a segment of a selectable marker, wherein DNAsegment D_(m1) of assembled polynucleotide A encodes a first segment ofa selectable marker and DNA segment D_(m2) of assembled polynucleotide Bencodes a second segment of the selectable marker, wherein DNA segmentD_(m1) and DNA segment D_(m2) comprise a region of homology sufficientto initiate host cell mediated homologous recombination, and whereinneither DNA segment D_(m1) nor DNA segment D_(m2) produces a functionalselectable marker, but whereupon homologous recombination by the hostcell a functional selectable marker is generated. Each assembledpolynucleotide further comprises a DNA segment D₀ encoding a chromosomaltargeting sequence of sufficient length to initiate host mediatedhomologous recombination, wherein DNA segment D₀₁ of assembledpolynucleotide A encodes an upstream chromosomal targeting sequence andDNA segment D₀₂ of assembled polynucleotide B encodes a downstreamchromosomal targeting sequence. Once inside the cell, the host cellrecombines assembled polynucleotide A and assembled polynucleotide B atthe region of homology in DNA segments D_(m1) and D_(m2) to form acombined polynucleotide. Moreover, the host cell uses the chromosomaltargeting sequences encoded by DNA segments D₀₁ and D₀₂ to insert thecombined polynucleotide by homologous recombination into its chromosome.Host cells comprising the combined polynucleotide can be readilyidentified based on the functional selectable marker generated.

In yet other embodiments, the methods comprise transforming a host cellwith a plurality of component polynucleotides and allowing the host cellto generate one or more assembled polynucleotides by homologousrecombination. The assembled polynucleotide can be extrachromosomallymaintained in the host cell or integrated into the chromosome of thehost cell. The generation of an exemplary assembled polynucleotide byhomologous recombination in a host cell and integration of the assembledpolynucleotide into the chromosome of the host cell is illustrated inFIG. 9. In the first step, an assembly composition comprising assemblyvectors is digested with a Type IIS restriction endonuclease such asSapI or LguI, resulting in the excision from the assembly vectorbackbones of component polynucleotides. In this embodiment, D₀ and D₃can be the upstream and downstream chromosomal targeting sequence, inwhich case the presence of a primer binding segment in the first andlast assembly vectors is optional. Alternatively, the two primer bindingsegments could function as the upstream and downstream genomic targetingsequences.

Once excised, each excised component polynucleotide comprises anannealable linker sequence LB that is homologous to an annealable linkersequence LA of another component polynucleotide and that is ofsufficient length to initiate host mediated homologous recombination.The component polynucleotide excised from the first assembly vectorfurther comprises an upstream chromosomal targeting sequence, and thecomponent polynucleotide excised from the last assembly vector furthercomprises a downstream chromosomal targeting sequence, wherein bothchromosomal targeting sequences are of sufficient length to initiatehost mediated homologous recombination with a chromosome of the hostcell. The restriction endonuclease can subsequently be inactivated. Inthe second step of the method, the components composition is introducedinto a host cell capable of homologous recombination. Once inside thecell, the host cell recombines the component polynucleotides at theregions of homology between the annealable linker sequences to form anassembled polynucleotide, and the assembled polynucleotide is integratedinto the chromosome. Host cells comprising the assembled polynucleotidecan be readily identified based on a selectable marker encoded by a DNAsegment of the assembled polynucleotide.

Any host cell can be used in the methods describe herein. In particularembodiments, suitable host cells are host cells that are capable ofrecombining polynucleotides based on complementary sequence stretchessuch as provided by the selectable marker segments, genomic targetingsequences, and annealable linker sequences provided herein. Illustrativeexamples of such host cells include but are not limited to Saccharomycescerevisiae. Conditions suitable for uptake of DNA by such host cells arewell known in the art.

Host cell transformants comprising an assembled or combinedpolynucleotide can be readily identified by virtue of expressing aselectable marker encoded by the assembled polynucleotide or by thecombined polynucleotide that permits selection for or against the growthof the cells. The selectable marker may be encoded by a single DNAsegment present in an assembly vector of an assembly composition.Alternatively, non-functional segments of the selectable marker may beencoded by DNA segments present in multiple assembly vectors of anassembly composition or in multiple assembled polynucleotides such thata functional selectable marker is generated only upon generation of anassembled polynucleotide or upon generation of a combinedpolynucleotide, respectively.

A wide variety of selectable markers are known in the art (see, forexample, Kaufinan, Meth. Enzymol., 185:487 (1990); Kaufman, Meth.Enzymol., 185:537 (1990); Srivastava and Schlessinger, Gene, 103:53(1991); Romanos et al., in DNA Cloning 2: Expression Systems, 2^(nd)Edition, pages 123-167 (IRL Press 1995); Markie, Methods Mol. Biol.,54:359 (1996); Pfeifer et al., Gene, 188:183 (1997); Tucker and Burke,Gene, 199:25 (1997); Hashida-Okado et al., FEBS Letters, 425:117(1998)). In some embodiments, the selectable marker is a drug resistantmarker. A drug resistant marker enables cells to detoxify an exogenousdrug that would otherwise kill the cell. Illustrative examples of drugresistant markers include but are not limited to those which conferresistance to antibiotics such as ampicillin, tetracycline, kanamycin,bleomycin, streptomycin, hygromycin, neomycin, Zeocin™, and the like. Inother embodiments, the selectable marker is an auxotrophic marker. Anauxotrophic marker allows cells to synthesize an essential component(usually an amino acid) while grown in media that lacks that essentialcomponent. Selectable auxotrophic gene sequences include, for example,hisD, which allows growth in histidine free media in the presence ofhistidinol. Other selectable markers include a bleomycin-resistancegene, a metallothionein gene, a hygromycin B-phosphotransferase gene,the AURI gene, an adenosine deaminase gene, an aminoglycosidephosphotransferase gene, a dihydrofolate reductase gene, a thymidinekinase gene, a xanthine-guanine phosphoribosyltransferase gene, and thelike.

Auxotrophy can also be used to identify host cell transformantscomprising a chromosomally integrated assembled or combinedpolynucleotide when the integration of the assembled or combinedpolynucleotide results in the disruption of a gene that the host cellrequires to synthesize a component essential for cell growth, thusrendering the cell auxotrophic.

Host cell transformants comprising a chromosomally integrated assembledor combined polynucleotide can also be identified by selecting host celltransformants exhibiting other traits encoded by individual DNA segmentsor by combinations of DNA segments, e.g., expression of peptides thatemit light, or by molecular analysis of individual host cell colonies,e.g., by restriction enzyme mapping, PCR amplification, or sequenceanalysis of isolated assembled polynucleotides or chromosomalintegration sites.

5.4 Combinatorial Methods of Polynucleotide Assembly and Host CellGeneration

In another aspect, the present invention provides rapid, robust, andhigh-throughput methods for the ordered assembly of multiple componentpolynucleotides into a plurality of assembled polynucleotides. Themethods rely on the use of an assembly composition comprising assemblyvectors that each comprise a DNA segment D, flanked by an annealablelinker sequence LA or LB, a pair of annealable linker sequences LA andLB, or by an annealable linker sequence and a primer binding segment,i.e., LA and PB or LB and PA, flanked by a pair of restriction sites RAand RB (FIG. 1B). However, to generate a diversity of assembledpolynucleotides using the methods disclosed herein, annealable linkersequences and primer binding segments are chosen such that more than onecombination of component polynucleotides can be assembled into anassembled polynucleotide in the reaction. Thus, in some embodiments, theassembly composition comprises at least two assembly vectors that havethe same annealable linker sequence LA or LB or the same primer bindingsegment PA or PB, but differ with respect to the DNA segment. In other70

embodiments, the assembly composition comprises at least two assemblyvectors that have the same pair of annealable linker sequences LA andLB, or the same annealable linker sequence and primer binding segmentpair, i.e., LA and PB or LB and PA but differ with respect to the DNAsegment.

FIG. 10 presents an exemplary method of generating a plurality ofassembled polynucleotides from seven (7) component polynucleotides inthe same reaction. Assembly vectors comprising DNA segments to beassembled are pooled in a single tube and digested with SapI to releasecomponent polynucleotide fragments from the assembly vector backbones.Following heat inactivation of SapI, the component polynucleotides aresubjected to denaturing conditions, followed by annealing conditionssufficient for hybridization of the complementary annealable linkerpairs. Following primer extension in the presence of DNA polymerase anddNTPs, primers complementary to primer binding segments PA and PB areadded to PCR amplify eight (8) different full-length assembledpolynucleotides that comprise DNA segments D_(01/02), D_(1/2), D₃, andD_(41/42) assembled in various possible combinations. Individualassembled polynucleotides can be isolated from the composition of mixedassembled polynucleotides, e.g., by another round of PCR amplificationusing primers complementary to regions of DNA segments D₀₁, D₀₂, D₄₁,and D₄₂. Alternatively, a set of assembled polynucleotides can beisolated by first and last assembly vectors comprising one of a group ofprimer binding segments PA and/or PB and using primers for PCRamplification that hybridize to only a select subgroup of primer bindingsegments PA and PB. The isolated assembled polynucleotides can be used,e.g., to transform host cells to generate a plurality of host cellscomprising assembled polynucleotides. Alternatively, host cells can bedirectly transformed with the composition of mixed assembledpolynucleotides and host cell transformants comprising each assembledpolynucleotide can be isolated, e.g., by molecular analysis ofindividual host cell colonies, or by selecting host cell transformantscomprising selectable markers or exhibiting other traits encoded byindividual DNA segments or by combinations of DNA segments.

In other embodiments, a plurality of host cells comprising a pluralityof polynucleotides assembled by combinatorial methods are generated bytransforming host cells with a composition comprising multiple assembledpolynucleotides of which at least two assembled polynucleotides comprisenon-functional segments of a selectable marker that upon homologousrecombination generate a functional selectable marker, and by selectinghost cells comprising a combined polynucleotide. FIG. 11 illustrates acombinatorial approach to generating a plurality of host cellscomprising combined polynucleotides. In the example, assembledpolynucleotides A1 and A2, each comprising the same upstream chromosomaltargeting sequence and the same first portion of a selectable marker,and assembled polynucleotides B1 and B2, each comprising the samedownstream chromosomal targeting sequence and the same second portion ofa selectable marker, are combinatorially combined by host cell mediatedhomologous recombination to generate four different combinedpolynucleotides, A1/B1, A1/B2, A2/B1, and A2/B2, that can be insertedinto a chromosome to generate four different host cells.

In yet other embodiments, a plurality of host cells comprising aplurality of polynucleotides assembled and combined by combinatorialmethods are generated by transforming host cells with a componentcomposition comprising multiple component polynucleotides of which atleast two component polynucleotides comprise non-functional segments ofa selectable marker that upon host cell mediated homologousrecombination generate a functional selectable marker, and by selectinghost cells comprising an assembled or combined polynucleotide.

5.5 Entry Vectors

In another aspect, provided herein is a vector, i.e., an entry vector,that can be used to prepare an assembly vector. In some embodiments, anentry vector is a circular polynucleotide that comprises a selectablemarker, an origin of replication, and a DNA segment immediately flankedby two restriction sites that facilitate the subcloning of different DNAsegments to be assembled in the assembly methods provided herein. Theentry vector further comprises one or two annealable linker sequences,or an annealable linker sequence and a primer binding segment, flankingthe restriction sites. The entry vector further comprises an additionalpair of restriction sites positioned at the outer flanks of the DNAsegment, e.g., that flank the one or two annealable linker sequences, orthe annealable linker sequence and primer binding segment. Thus, in someembodiments, the entry vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, anannealable linker sequence LA, a restriction site RY, a DNA segment D, arestriction site RZ, and a restriction site RB. In other embodiments,the entry vector is a circular polynucleotide that comprises, in a 5′ to3′ orientation, a restriction site RA, a restriction site RY, a DNAsegment D, a restriction site RZ, an annealable linker sequence LB, anda restriction site RB. In other embodiments, the entry vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, a primer binding segment PA or an annealable linkersequence LA, a restriction site RY, a DNA segment D, a restriction siteRZ, a primer binding segment PB or an annealable linker sequence LB, anda restriction site RB.

In some embodiments, the sequence of the DNA segment D of the entryvector is the lac Z reporter gene. The lac Z reporter gene is useful forfacilitating blue/white selection of colonies transformed with vectorscomprising DNA segments other than lac Z, e.g., during the preparationof an assembly vector described herein.

In some embodiments, the entry vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, anannealable linker sequence LA, a restriction site RY, a DNA segment D, arestriction site RZ, and a restriction site RB (i.e.,5′-RA-LA-RY-D-RZ-RB-3′). In some embodiments, the entry vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, a restriction site RY, a DNA segment D, arestriction site RZ, an annealable linker sequence LB, and a restrictionsite RB (i.e., 5′-RA-RY-D-RZ-LB-RB-3′). In some embodiments, the entryvector is a circular polynucleotide that comprises, in a 5′ to 3′orientation, a restriction site RA, an annealable linker sequence LA, arestriction site RY, a DNA segment D, a restriction site RZ, anannealable linker sequence LB, and a restriction site RB (i.e.,5′-RA-LA-RY-D-RZ-LB-RB-3′). In some embodiments, the entry vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, a primer binding segment PA, a restriction site RY,a DNA segment D, a restriction site RZ, an annealable linker sequenceLB, and a restriction site RB (i.e., 5′-RA-PA-RY-D-RZ-LB-RB-3′). In someembodiments, the entry vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, anannealable linker sequence LA, a restriction site RY, a DNA segment D, arestriction site RZ, a primer binding segment PB, and a restriction siteRB (i.e., 5′-RA-LA-RY-D-RZ-PB-RB-3′). An exemplary entry vector isprovided in FIG. 1A.

The primer binding segment can be any nucleotide sequence that is notcomplementary with any of the annealable linker sequences that are usedto make an assembled polynucleotide. In some embodiments, the two primerbinding segment includes a restriction endonuclease recognition andcleavage site. In some embodiments, the primer binding segment is simplyone of the available linker sequences that are not being used in aparticular assembly reaction. In some embodiments, the nucleic acidsequence of primer binding segment PA is selected from the groupconsisting of SEQ ID NOS: 24 and 25. In some embodiments, the nucleicacid sequence of primer binding segment PB is selected from the groupconsisting of SEQ ID NOS: 24 and 25. In some embodiments, the nucleicacid sequences of primer binding segment PA and primer binding segmentPB are selected from the group consisting of SEQ ID NOS: 24 and 25. Inpreferable embodiments, PA and PB are not identical in sequence.

In some embodiments, the nucleic acid sequence of annealable linkersequence LA or LB is at least 24 nucleotides and has a T_(m) of at least60° C. In some embodiments, the nucleic acid sequence of annealablelinker sequence LA is selected from the group consisting of SEQ ID NOS:1 to 23. In some embodiments, the nucleic sequence of annealable linkersequence LB is selected from the group consisting of SEQ ID NOS: 1 to23. In some embodiments, the nucleic sequences of annealable linkersequence LA and annealable linker sequence LB are selected from thegroup consisting of SEQ ID NOS: 1 to 23.

The restriction sites RY and RZ can be utilized as cloning sites tointroduce various DNA segments for the generation of an assembly vector.In some embodiments, RY and RZ are not identical in sequence. In someembodiments, RY and RZ are cleavable by the same restrictionendonuclease. In some embodiments, RY and RZ are identical in sequence.In some embodiments, restriction sites RY and RZ are cleavable by arestriction endonuclease that generates staggered ends, i.e. terminihaving a 5′ or 3′ overhang. In other embodiments, restriction sites RYand RZ are cleavable by a restriction endonuclease that generates bluntends.

Although restriction sites RY and RZ can be any restriction site knownin the art, restriction sites recognized by the Type IIS restrictionendonucleases are particularly useful. Type IIS restrictionendonucleases have DNA binding domains that are distinct from theircleavage domains. Therefore, they recognize a specific sequence butcleave at a defined distance away. For example, the Type IIS restrictionendonuclease SchI (which is also known as MlyI) binds to a recognitionsite containing the sequence GAGTC and cleaves four (4) base pairs awayfrom the recognition site, creating a blunt ended DNA molecule. Type IISrestriction sites are particularly useful for the preparation of anassembly vector from an entry vector. For example, in a subcloningprocedure wherein the DNA segment of an entry vector, for example lacZ,is replaced with a DNA segment of interest, excision of lacZ with a TypeIIS restriction endonuclease can result in complete removal of therestriction site recognition sequence. As a result, upon ligation of theDNA segment of interest to the linearized entry vector, extraneoussequence between the annealable linker sequence or the primer bindingsegment and the newly introduced DNA segment is minimized.

Thus, in some embodiments, restriction sites RY and RZ are restrictionsites recognizable and cleavable by any Type IIS restrictionendonuclease known in the art. Suitable Type IIS restrictionendonucleases include but are not limited to the following endonucleasesand their isoschizomers, which are indicated in parentheses: Alw26I(BsmAI), AlwI (AclWI, BinI), AsuHPI (HphI), BbvI (Bst71I), BcefI, BstF5I(BseGI, FokI), FauI, HgaI, SapI (LguI), MboII, PleI, SapI, SchI (MlyI),SfaNI, and TspRI, AceIII, BbsI (BbvII, BpiI, BpuAI), Bce83I, BciVI, BfiI(BmrI), BpmI (GsuI), BsaI (Eco31I), BseRI, BsgI, BsmBI (Esp3I), BsmFI,BspMI, BsrDI (Bse3DI), Bsu6I (Eam1104I, EarI, Ksp632I), Eco57I, FauI,MmeI, RleAI, TaqII, and Tth111II. In particular embodiments, restrictionsites RY and RZ are recognizable and cleavable by the SchI restrictionendonuclease.

In some embodiments, RA and RB are not identical in sequence. In someembodiments, RA and RB are cleavable by the same restrictionendonuclease. In some embodiments, RA and RB are identical in sequence.In some embodiments, restriction sites RA and RB are cleavable by arestriction endonuclease that generates staggered ends, i.e. terminihaving a 5′ or 3′ overhang. In other embodiments, restriction sites RAand RB are cleavable by a restriction endonuclease that generates bluntends.

Although restriction sites RA and RB can be any restriction sites knownin the art, restriction sites that are relatively infrequent in DNA(e.g., cDNA) of one or more organisms (i.e., an infrequent cutter) areparticularly useful. In some embodiments, restriction sites RA and RBare recognizable and cleavable by a restriction endonuclease that hasrelatively infrequent restriction sites in human DNA. In someembodiments, restriction sites RA and RB are recognizable and cleavableby a restriction endonuclease that has relatively infrequent restrictionsites in mouse DNA. In some embodiments, restriction sites RA and RB arerecognizable and cleavable by a restriction endonuclease that hasrelatively infrequent restriction sites in yeast DNA, for example, inthe DNA of Saccharomyces cerevisiae, Pichia pastoris, Kluyveromyceslactis, Arxula adeninivorans, or Hansenula polymorpha. In someembodiments, restriction sites RA and RB are recognizable and cleavableby a restriction endonuclease that has relatively few restriction sitesin the DNA of bacteria, for example, in the DNA of Escherichia coli orBacillus subtilis.

In some embodiments, restriction sites RA and RB are recognizable andcleavable by a Type IIS restriction endonuclease wherein the recognitionsite is distal to the polynucleotide sequence comprising, e.g.,PA/LA-D-PB/LB. In some embodiments, each restriction site RA and RB isindependently recognizable and cleavable by a restriction endonucleaseselected from the group consisting of MssI, NruI (Bsp68I, MluB2I,Sbo13I, SpoI), SnaBI (BstSNI, Eco105I), SrfI, and SwaI (BstRZ246I,BstSWI, MspSWI, SmiI), HpaI, HincII, PshAI, OliI, AluI, Alw26I, BalI,DraI, DpnI, EcoR47III, EcoRCRI, EcoRV, FokI, HaeIII, HincII, MboI,MspA1I, NaeI, RsaI, PvuII, ScaI, SmaI, SspI, StuI, XmnI, EcaBC3I, SciI,HincII, DraI, BsaBI, Cac8I, Hpy8I, MlyI, PshAI, SspD51, BfrBI, BsaAI,BsrBI, BtrI, CdiI, CviJI, CviRI, Eco47III, Eco78I, EcoICRI, FnuDII,FspAI, HaeI, LpnI, MlyI, MslI, MstI, NaeI, NlaIV, NruI, NspBII, OliI,PmaCI, PshAI, PsiI, SrfI, StuI, XcaI, XmnI, ZraI, and isoschizomersthereof. In a particular embodiment, restriction sites RA and RB arerecognizable and cleavable by the SapI or LguI restriction endonuclease.LguI is an isoschizomer of SapI having the same recognition and cleavagespecificity.

In some embodiments, the entry vector provided herein also comprises oneor more nucleic acid sequences that generally have some function in thereplication, maintenance, or integrity of the vector (e.g., origins ofreplication) as well as one or more selectable markers. Replicationorigins are unique polynucleotides that comprise multiple short repeatedsequences that are recognized by multimeric origin-binding proteins andthat play a key role in assembling DNA replication enzymes at the originsite. Suitable origins of replication for use in the entry and assemblyvectors provided herein include but are not limited to E. coli oriC,colE1 plasmid origin, 2μ and ARS (both useful in yeast systems), sfl,SV40 EBV oriP (useful in mammalian systems), or those found in pSC101.Selectable markers can be useful elements in vectors as they provide ameans to select for or against growth of cells that have beensuccessfully transformed with a vector containing the selectable markerand express the marker.

In some embodiments, any vector may be used to construct the entryvector as provided herein. In particular, vectors known in the art andthose commercially available (and variants or derivatives thereof) maybe engineered to include a restriction site RA, optionally a primerbinding segment PA or an annealable linker sequence LA, a restrictionsite RY, a DNA segment D, a restriction site RZ, optionally a primerbinding segment PB or an annealable linker sequence LB, and arestriction site RB, for use in the methods provided herein. Suchvectors may be obtained from, for example, Vector Laboratories Inc.,InVitrogen, Promega, Novagen, NEB, Clontech, Boehringer Mannheim,Pharmacia, EpiCenter, OriGenes Technologies Inc., Stratagene, PerkinElmer, Pharmingen, Life Technologies, Inc., and Research Genetics.General classes of vectors of particular interest include prokaryoticand/or eukaryotic cloning vectors, expression vectors, fusion vectors,two-hybrid or reverse two-hybrid vectors, shuttle vectors for use indifferent hosts, mutagenesis vectors, transcription vectors, vectors forreceiving large inserts, and the like. Other vectors of interest includeviral origin vectors (M13 vectors, bacterial phage λ vectors, adenovirusvectors, and retrovirus vectors), high, low and adjustable copy numbervectors, vectors that have compatible replicons for use in combinationin a single host (PACYC184 and pBR322) and eukaryotic episomalreplication vectors (pCDM8).

In particular embodiments, entry vectors for use in accordance with themethods provided herein are the pRYSE vectors, having the nucleotidesequences of SEQ ID NO: 207 through 221. A schematic of the pRYSEvectors is provided in FIG. 4, and the preparation of the pRYSE vectorsis described in Example 1 below.

5.6 Assembly Vectors

In another aspect, provided herein is a vector, i.e., an assemblyvector, that can be used in the assembly of a plurality of componentpolynucleotides into one or more assembled polynucleotides. In someembodiments, an assembly vector is a circular polynucleotide thatcomprises a selectable marker, an origin of replication, and a DNAsegment flanked by an annealable linker sequence, an annealable linkersequence pair, or by an annealable linker sequence/primer bindingsegment pair, flanked by a pair of restriction sites. The restrictionsites can serve to facilitate excision of the component polynucleotidefrom the assembly vector backbone during the assembly reaction. Thus, insome embodiments, the assembly vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, a primerbinding segment PA or an annealable linker sequence LA, a DNA segment D,and a restriction site RB. In some embodiments, the assembly vector is acircular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, a DNA segment D, a primer binding segment PB or anannealable linker sequence LB, and a restriction site RB. In certainembodiments, the assembly vector is a circular polynucleotide thatcomprises, in a 5′ to 3′ orientation, a restriction site RA, a primerbinding segment PA or an annealable linker sequence LA, a DNA segment D,a primer binding segment PB or an annealable linker sequence LB, and arestriction site RB.

In some embodiments, the assembly vector is a circular polynucleotidethat comprises, in a 5′ to 3′ orientation, a restriction site RA, anannealable linker sequence LA, a DNA segment D, and a restriction siteRB (i.e., 5′-RA-LA-D-RB-3′). In some embodiments, the assembly vector isa circular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, a DNA segment D, an annealable linker sequence LB,and a restriction site RB (i.e., 5′-RA-D-LB-RB-3′). In some embodiments,the assembly vector is a circular polynucleotide that comprises, in a 5′to 3′ orientation, a restriction site RA, an annealable linker sequenceLA, a DNA segment D, an annealable linker sequence LB, and a restrictionsite RB (i.e., 5′-RA-LA-D-LB-RB-3′). In some embodiments, the assemblyvector is a circular polynucleotide that comprises, in a 5′ to 3′orientation, a restriction site RA, a primer binding segment PA, a DNAsegment D, an annealable linker sequence LB, and a restriction site RB(i.e., 5′-RA-PA-D-LB-RB-3′). In some embodiments, the assembly vector isa circular polynucleotide that comprises, in a 5′ to 3′ orientation, arestriction site RA, an annealable linker sequence LA, a DNA segment D,a primer binding segment PB, and a restriction site RB (i.e.,5′-RA-LA-D-PB-RB-3′). Exemplary assembly vectors are provided in FIG. 1Band FIG. 2.

In some embodiments, the nucleic acid sequence of primer binding segmentPA is selected from the group consisting of SEQ ID NOS: 24 and 25. Insome embodiments, the nucleic acid sequence of primer binding segment PBis selected from the group consisting of SEQ ID NOS: 24 and 25. In someembodiments, the nucleic acid sequences of primer binding segment PA andprimer binding segment PB are selected from the group consisting of SEQID NOS: 24 and 25. In preferable embodiments, the nucleic acid sequencesof primer binding segment PA and primer binding segment PB are notidentical.

In some embodiments, the nucleic acid sequence of annealable linkersequence LA or LB is at least 24 nucleotides and has a T_(m) of at least60° C. In some embodiments, the nucleic acid sequence of annealablelinker sequence LA is selected from the group consisting of SEQ ID NOS:1 to 23. In some embodiments, the nucleic acid sequence of annealablelinker sequence LB is selected from the group consisting of SEQ ID NOS:1 to 23. In some embodiments, the nucleic acid sequences of annealablelinker sequence LA and annealable linker sequence LB are selected fromthe group consisting of SEQ ID NOS: 1 to 23.

In some embodiments, RA and RB are not identical in sequence. In someembodiments, RA and RB are cleavable by the same restrictionendonuclease. In some embodiments, RA and RB are identical in sequence.In some embodiments, restriction sites RA and RB are cleavable by arestriction endonuclease that generates staggered ends, i.e. terminihaving a 5′ or 3′ overhang. In other embodiments, restriction sites RAand RB are cleavable by a restriction endonuclease that generates bluntends.

Although restriction sites RA and RB can be any restriction sites knownin the art, restriction sites that are relatively infrequent in DNA(e.g., cDNA) of one or more organisms (i.e., an infrequent cutter) areparticularly useful. In some embodiments, restriction sites RA and RBare recognizable and cleavable by a restriction endonuclease that hasrelatively infrequent restriction sites in human DNA. In someembodiments, restriction sites RA and RB are recognizable and cleavableby a restriction endonuclease that has relatively infrequent restrictionsites in mouse DNA. In some embodiments, restriction sites RA and RB arerecognizable and cleavable by a restriction endonuclease that hasrelatively infrequent restriction sites in yeast DNA, for example, inthe DNA of Saccharomyces cerevisiae, Pichia pastoris, Kluyveromyceslactis, Arxula adeninivorans, or Hansenula polymorpha. In someembodiments, restriction sites RA and RB are recognizable and cleavableby a restriction endonuclease that has relatively few restriction sitesin the DNA of bacteria, for example, in the DNA of Escherichia coli orBacillus subtilis.

In some embodiments, restriction sites RA and RB are recognizable andcleavable by a Type IIS restriction endonuclease. Illustrative examplesof suitable Type IIS restriction endonucleases include but are notlimited to: MssI, NruI (Bsp68I, MluB2I, Sbo13I, SpoI), SnaBI (BstSNI,Eco105I), SrfI, and SwaI (BstRZ246I, BstSWI, MspSWI, SmiI), HpaI,HincII, PshAI, OliI, AluI, Alw26I, BalI, DraI, DpnI, EcoR47III, EcoRCRI,EcoRV, FokI, HaeIII, HincII, MboI, MspA1I, NaeI, RsaI, PvuII, ScaI,SmaI, SspI, StuI, XmnI, EcaBC3I, SciI, HincII, DraI, BsaBI, Cac8I,Hpy8I, MlyI, PshAI, SspD51, BfrBI, BsaAI, BsrBI, BtrI, CdiI, CviJI,CviRI, Eco47III, Eco78I, EcoICRI, FnuDII, FspAI, HaeI, LpnI, MlyI, MslI,MstI, NaeI, NlaIV, NruI, NspBII, OliI, PmaCI, PshAI, PsiI, SrfI, StuI,XcaI, XmnI, ZraI, or isoschizomers thereof. In a particular embodiment,restriction sites RA and RB are recognizable and cleavable by the SapIor LguI restriction endonuclease.

Preferably, the DNA segment of an assembly vector does not comprise anucleic acid sequence that can be recognized and cleaved by arestriction endonuclease that can cleave any of restriction sites RA andRB within the assembly vector. This ensures that the DNA segment remainsintact during the first stage of the assembly reaction, during which thecomponent polynucleotide is excised from the assembly vector backbone.In particular embodiments, the DNA segment does not comprise a SapI/LguIsite and RA and RB are cleavable by SapI or LguI. Site-directedmutagenesis (see Carter, Bi°Chem. J. 237:1-7 (1986); Zoller and Smith,Methods Enzymol. 154:329-50 (1987)), cassette mutagenesis, restrictionselection mutagenesis (Wells et al., Gene 34:315-323 (1985)),oligonucleotide-mediated (site-directed) mutagenesis, PCR mutagenesis,or other known techniques can be performed to modify any such sequencewithin the DNA segment either before or after ligation of the DNAsegment to the entry vector.

In some embodiments, the assembly vector provided herein also comprisesone or more nucleic acid sequences that generally have some function inthe replication, maintenance, or integrity of the vector (e.g., originsof replication) as well as one or more selectable markers. Replicationorigins are unique polynucleotides that comprise multiple short repeatedsequences that are recognized by multimeric origin-binding proteins andthat play a key role in assembling DNA replication enzymes at the originsite. Suitable origins of replication for use in the entry and assemblyvectors provided herein include but are not limited to E. coli oriC,colE1 plasmid origin, 2μ and ARS (both useful in yeast systems), sfl,SV40 EBV oriP (useful in mammalian systems), or those found in pSC101.Selectable markers can be useful elements in vectors as they provide ameans to select for or against growth of cells that have beensuccessfully transformed with a vector containing the selectable markerand express the marker.

In some embodiments, any vector may be used to construct the assemblyvector as provided herein. In particular, vectors known in the art andthose commercially available (and variants or derivatives thereof) maybe engineered to include a restriction site RA, a primer binding segmentPA or an annealable linker sequence LA, a DNA segment D, a primerbinding segment PB or an annealable linker sequence LB, and arestriction site RB, for use in the methods provided herein. Suchvectors may be obtained from, for example, Vector Laboratories Inc.,InVitrogen, Promega, Novagen, NEB, Clontech, Boehringer Mannheim,Pharmacia, EpiCenter, OriGenes Technologies Inc., Stratagene, PerkinElmer, Pharmingen, Life Technologies, Inc., and Research Genetics.General classes of vectors of particular interest include prokaryoticand/or eukaryotic cloning vectors, expression vectors, fusion vectors,two-hybrid or reverse two-hybrid vectors, shuttle vectors for use indifferent hosts, mutagenesis vectors, transcription vectors, vectors forreceiving large inserts, and the like. Other vectors of interest includeviral origin vectors (M13 vectors, bacterial phage λ vectors, adenovirusvectors, and retrovirus vectors), high, low and adjustable copy numbervectors, vectors that have compatible replicons for use in combinationin a single host (PACYC184 and pBR322) and eukaryotic episomalreplication vectors (pCDM8).

An assembly vector can be prepared from an entry vector. To prepare anassembly vector from an entry vector, the entry vector can be digestedwith one or more restriction endonucleases capable of cleaving RY and RZthereby linearizing the vector such that it can accept a DNA segment.The DNA segment can be ligated into RY and RZ sites using standardcloning techniques to generate an assembly vector of the invention. Forexample, the DNA segment may be obtained by standard procedures known inthe art from cloned DNA (e.g., a DNA “library”), by chemical synthesis,by cDNA cloning, or by the cloning of genomic DNA, or fragments thereof,purified from the desired cell, or by PCR amplification and cloning.See, for example, Sambrook et al., Molecular Cloning, A LaboratoryManual, 3d. ed., Cold Spring Harbor Laboratory Press, Cold SpringHarbor, N.Y. (2001); Glover, D. M. (ed.), DNA Cloning: A PracticalApproach, 2d. ed., MRL Press, Ltd., Oxford, U.K. (1995).

An assembly vector can also be prepared from another vector that doesnot comprise an annealable linker sequence, an annealable linkersequence pair, or an annealable linker sequence/primer binding segmentpair flanking the site of insertion of the DNA segment. To prepare anassembly vector from such a vector, the vector can be digested with oneor more restriction endonucleases capable of cleaving the vector at asite suitable for insertion of a DNA fragment, e.g., at a multiplecloning site, thereby linearizing the vector such that it can accept aDNA fragment. The DNA fragment to be inserted can be obtained bystandard procedures known in the art such as, for example, cloning,chemical synthesis, or PCR amplification. The DNA fragment comprises aDNA segment flanked by an annealable linker sequence, an annealablelinker sequence pair or an annealable linker sequence/primer bindingsegment pair. Thus, in some embodiments, the DNA fragment comprises, ina 5′ to 3′ orientation, an annealable linker sequence LA or a primerbinding segment PA, a DNA segment D, and an annealable linker sequenceLB or a primer binding segment PB (i.e., 5′-LA-D-LB-3′ or 5′-PA-D-LB-3′or 5′-LA-D-PB-3′). In some embodiments, the DNA fragment comprises, in a5′ to 3′ orientation, a DNA segment D, and an annealable linker sequenceLB or a primer binding segment PB (i.e., 5′-D-LB-3′ or 5′-D-PB-3′). Insome embodiments, the DNA fragment comprises, in a 5′ to 3′ orientation,an annealable linker sequence LA or a primer binding segment PA, and aDNA segment D, (i.e., 5′-LA-D-3′ or 5′-PA-D-3′). The DNA fragment canfurther comprise a pair of restriction sites that flank the annealablelinker sequence, the annealable linker sequence pair or the annealablelinker sequence/primer binding segment pair and that upon cleavage by arestriction endonuclease produce termini that are compatible withtermini produced by linearising the vector into which the DNA fragmentis to be inserted. Alternatively, the DNA fragment can generated suchthat it contains such compatible termini and does not require additionaldigestion with a restriction endonuclease to produce the compatibletermini. Upon ligation of the DNA fragment with the linearized vector togenerate an assembly vector, the restriction sites used to generate thecompatible termini may be preserved to serve as restriction sites RA andRB of the assembly vector. Alternatively, the ligation may remove theoriginal restriction sites but additional restriction sites may bepresent in the linearised vector that can serve as restriction sites RAand RB of the assembly vector.

Exemplary methods for generating an assembly vector from an entry vector(i.e., a pRYSE vector) or from another vector (i.e., a pMULE vector) areprovided in Example 6 below.

5.7 Annealable Linker Sequences

In another aspect, provided herein are annealable linker sequences thatflank the DNA segment located within entry vectors and assembly vectors.Annealable linker sequences provide sequence overlap between adjacentcomponent polynucleotides in an assembly reaction, and thus serve toprime a component polynucleotide for assembly into an assembledpolynucleotide. Thus, in preferred embodiments, the annealable linkersequences LA and LB of the entry and assembly vectors are optimized toprovide efficient and accurate priming to complementary annealablelinker sequences during an assembly reaction.

In some embodiments, the length of an annealable linker sequence is longenough to provide adequate specificity with its complement annealablelinker sequence, yet short enough to readily anneal to its complementannealable linker sequence at the annealing temperature of the assemblyreaction. In some embodiments the length of an annealable linkersequence is long enough to allow for host cell mediated homologousrecombination with its complement annealable linker sequence.

In some embodiments, the annealable linker sequence is about 5, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 nucleotides inlength. In some embodiments, the annealable linker sequence is at least10, 12, 14, 16, 18, 20, 22, 24, 26, 28, or 30 nucleotides in length. Insome embodiments, the annealable linker sequence is greater than 30, 40,50, 60, 70, 80, 90, 100, 500, 1000, 5000, or 10,000 nucleotides inlength. In some embodiments, the annealable linker is at least 18nucleotides in length and is a number divisible by three, so as tofacilitate read-through transcription of the linker when ligated to anencoding DNA segment. In particular embodiments, the annealable linkeris 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, or 60nucleotides in length.

In some embodiments, an annealable linker sequence has a relatively highmelting temperature (T_(m)), i.e., the temperature at which one half ofan annealed annealable linker sequence duplex will dissociate to becomesingle stranded. The T_(m) of an annealable linker can be calculatedaccording to SantaLucia, PNAS, 95:-1460-1465 (1998) using a nearestneighbor algorithm. A relatively high T_(m) may provide for morespecific priming during an assembly reaction. A relatively high T_(m)may also allow combination of the annealing and extension steps of PCRor reduce the amount of time needed to adjust temperatures between theannealing and extension steps of PCR and thus enable greater efficiencyin using the assembly methods of the invention. Thus, in someembodiments, an annealable linker sequence duplex has a T_(m) of about60° C.-80° C. In some embodiments, an annealable linker sequence duplexhas a T_(m) of about 65° C.-75° C. In some embodiments, an annealablelinker sequence duplex has a T_(m) of greater than 50° C., 55° C., 60°C., 65° C., 70° C., 75° C., 80° C., 85° C., or 90° C.

In some embodiments, annealable linker sequences do not form appreciablesecondary structures (e.g., hairpins, self-dimers) produced viaintramolecular (i.e., within the same molecule) interactions under theconditions of the methods described herein, either at the DNA level orat the RNA level or at both the DNA and the RNA level. The presence ofsecondary structures in DNA can lead to poor or no assembledpolynucleotide yield of the assembly reaction. The presence of secondarystructures in RNA can lead to decreased translation efficiencies, whichare of particular concern when the annealable linker sequence is used toassemble component polynucleotides comprising a promoter and a proteincoding sequence into a assembled polynucleotide in which the annealablelinker sequence is positioned between the promoter and the proteincoding sequence. Accordingly, annealable linker sequences useful in theassembly methods of the invention are designed to not form secondary RNAand/or DNA structures. The ability of an annealable linker sequence toform secondary RNA or DNA structures can be determined using softwaretools such as, for example, IDT Oligo Analyzer (Integrated DNATechnologies, Coralville, Iowa), mFold (Zuker 2003 Nucleic Acids Res. 31(13), 3406-15), or RNAfold (Hofacker & Stadler (2006) Bioinformatics 22(10): 1172-6). In general, these tools calculate the Gibbs free energy(ΔG) for transition of a sequence from the linear to the folded state.The larger ΔG, the less likely that the sequence will form a secondarystructure. Accordingly, in some embodiments, annealable linker sequencesare designed to have large ΔG values for the transition from linear tofolded states. In some embodiments, annealable linker sequences aredesigned to have ΔG values for the transition from linear to foldedstates that are equal to or greater than the ΔG values for thetransition from linear to folded states of the n-bases that lieimmediately upstream of the coding sequences of highly expressed genesin the Saccharomyces cerevisiae genome, wherein n represents an integerthat corresponds to the number of bases in the annealable linkersequence. In some embodiments, annealable linker sequences are 36 baseslong and have a ΔG value for the transition from linear to folded statesof −1 or greater.

In some embodiments, annealable linker sequences are also designed toavoid unintended intermolecular interactions (i.e., between differentmolecules). Thus, in some embodiments, an annealable linker sequencedoes not anneal substantially with any other sequences within theassembly vector that contains the annealable linker sequence (e.g.,vector backbone sequences) and/or with any other sequences within otherassembly vectors of the assembly compositions aside from thecomplementary annealable linker sequences required for polynucleotideassembly by the methods provided herein. In some embodiments, anannealable linker sequence does not anneal substantially with otherannealable linker sequences within assembly vectors of the assemblycompositions provided herein.

In some embodiments, an annealable linker sequence has a high G-Ccontent, i.e., the number of guanine and cytosine nucleotides in theannealable linker sequence as a percentage of the total number of basesin the annealable linker sequence Annealable linker sequences that havea high G-C content are generally useful in the methods of the inventionbecause a high G-C content generally provides for a high T_(m), which inturn may provide for more specific priming during an assembly reactionand for time and process savings by allowing combination of theannealing and extension steps of SOE/PCR. In some embodiments, the G-Ccontent of the annealable linker sequence is between about 20-80%. Insome embodiments, the G-C content of the annealable linker sequence isbetween about 40-60%. In some embodiments, the G-C content of theannealable linker sequence is about 40, 45, 50, 55, 60, or 70%. Inparticular embodiments, an annealable linker sequence has a G-C contentof greater than 70%. Illustrative examples of annealable linkersequences that have a high G-C content, do not form appreciablesecondary DNA structures, and have a T_(m) of 70° C. or greater are SEQID NOS: 1 to 8.

In some embodiments, an annealable linker sequence has a high A-Tcontent, i.e., the number of adenine and thymine nucleotides in theannealable linker sequence as a percentage of the total number of basesin the annealable linker sequence. A high A-T content may provide forreduced propensity of the annealable linker sequence to form substantialsecondary structures, which may be of particular concern when theannealable linker sequence is used to assemble component polynucleotidescomprising a promoter and a protein coding sequence into a assembledpolynucleotide in which the annealable linker sequence is positionedbetween the promoter and the protein coding sequence. In someembodiments, the A-T content of the annealable linker sequence isbetween about 20-80%. In some embodiments, the A-T content of theannealable linker sequence is between about 40-60%. In some embodiments,the A-T content of the annealable linker sequence is about 30, 35, 40,45, 50, 55, or 60%. In some embodiments, the annealable linker sequencehas an A-T content of greater than 30%. In some embodiments, thesequence of the 3′-most 26 bases of an annealable linker sequencefulfills the following consensus motif: 5′ANNNNNNNNANNNAANTANNTTNANA-3′(SEQ ID NO: 248), wherein A stands for adenine, N for any motif, have arelatively high A-T content, do not form appreciable secondary RNA orDNA structures, nucleotide, and T for thymine. This consensus motif isfrequently found in the 26 bases that lie upstream of the start codonsof highly expressed genes in the genome of Saccharomyces cerevisiae.Illustrative examples of annealable linker sequences that comprise thisconsensus motif, have a relatively high A-T content, do not formappreciable secondary RNA or DNA structures, and have a T_(m) of 65° C.or greater are SEQ ID NOS: 9 to 23.

In some embodiments, an annealable linker sequence comprises one or morerestriction sites. Incorporation of restriction sites into an annealablelinker sequence allows for the excision of a DNA segment from an entryor assembly vector while maintaining the restriction sites RA and RBwithin the entry vector or assembly vector. Restriction sites within theannealable linker sequence also facilitate directional subcloning of DNAsegments into other entry or assembly vectors. This feature facilitatesthe efficient construction of assembly vectors comprising the same DNAsegment but having different annealable linker sequence pairs or primerbinding segment/annealable linker sequence pairs, for instance, togenerate a library of assembly vectors comprising different annealablelinker sequence pairs as described below. This feature can also obviatethe need to re-amplify and sequence a DNA segment to create additionalassembly vectors comprising the DNA segment. Thus, in some embodiments,the annealable linker sequence comprises a unique restriction site. Insome embodiments, the restriction site is a 7-base pair restrictionsite, i.e., is cleavable by a restriction endonuclease that recognizes a7-base pair nucleotide sequence. In some embodiments, the restrictionsite is a 8-base pair restriction site. In particular embodiments, therestriction site within the annealable linker sequence is recognized andcleavable by MreI, FseI, SbfI, AsiSI, NotI, AscI, or BbvCI.

In some embodiments, the annealable linker sequence comprises a sequencethat allows for read-through transcription once the linker is ligated toan encoding DNA segment. In some embodiments, an annealable linkersequence allows for read-through transcription in both the 5′ to 3′ and3′ to 5′ orientation. In these embodiments, the length of the annealablelinker sequence, preferably, is a number of nucleotides divisible bythree (3).

In particular embodiments, an annealable linker sequence does notcomprise codons that are rarely used in Escherichia coli (E. coli) orSaccharomyces cerevisiae (S. cerevisiae). Efficient expression ofheterologous genes in E. coli or S. cerevisiae can be adversely affectedby the presence of infrequently used codons, and expression levels ofthe heterologous protein often rise when rare codons are replaced bymore common ones. See, e.g., Williams et al., Nucleic Acids Res. 16:10453-10467, 1988 and Hoog et al., Gene 43: 13-21, 1986. Accordingly, anannealable linker sequence that comprises a read-through sequencepreferably does not comprise rare codons used in E. coli or S.cerevisiae, so as to enable efficient expression of proteins encoded bya assembled polynucleotide comprising the annealable linker sequence.

In some embodiments, the set of annealable linker sequences are uniquesequences that are not found in an intended host organism. In someembodiments, the set of annealable linker sequences are unique sequencesthat are not found in E. coli. In other embodiments, the set ofannealable linker sequences are unique sequences that are not found inS. cerevisiae.

In some embodiments, suitable annealable linker sequences are identifiedin a test assembled polynucleotide. A test assembled polynucleotidecomprises the annealable linker sequence to be tested and additionalelements that permit testing of the annealable linker sequence. Forexample, to test whether an annealable linker is suitable for assemblinga first component polynucleotide comprising a promoter sequence and asecond component polynucleotide comprising a protein coding sequence tobe put under the control of the promoter in the assembledpolynucleotide, a test assembled polynucleotide can be assembled fromthe first component polynucleotide comprising, in a 5′ to 3′orientation, a primer binding segment or an annealable linker sequence,a DNA segment comprising the promoter, and the annealable linkersequence to be tested, and the second component polynucleotidecomprising, in a 5′ to 3′ orientation, the annealable linker sequence tobe tested, a DNA segment encoding a reporter gene (e.g., greenfluorescent protein (GFP)), and a primer binding segment or annealablelinker sequence. The test assembled polynucleotide can be tested in vivoor in vitro for the efficiency of expression of the reporter gene.Similar test assembled polynucleotides can be assembled to test thesuitability of annealable linker sequences for assembling componentpolynucleotides comprising DNA segments comprising other elements, suchas an enhancer, terminator, poly-A tail, nuclear localization signal,mRNA stabilization signal, selectable marker, epitope tag codingsequence, degradation signal, and the like. The test assembledpolynucleotide may comprise additional component polynucleotides thatenable testing, such as for example, genomic targeting sequences andselectable markers that enable introduction of the test assembledpolynucleotide into host cells and selection of positive transformantsfor in vivo testing.

Table 1 presents the T_(m), restriction sites, and read-through aminoacids of exemplary annealable linker sequences corresponding to SEQ IDNOS: 1-23.

TABLE 1 Sequence and Characteristics of Annealable Linker SequencesAnnealable Melt Restriction Linker Seq. Length % % Temp. EnzymeRead-Through Amino Acids Sequence Name (bases) G-C A-T (T_(m)) Site FwdRev SEQ ID NO: 1 RYSE 1 24 79.2 20.8 72.4 SEQ ID NO: 2 RYSE 2 24 75.025.0 71.4 MreI SEQ ID NO: 3 RYSE 3 24 75.0 25.0 73.7 FseI TAGQARGD (SEQID NO: 249) SEQ ID NO: 4 RYSE 4 24 70.8 29.2 71.5 SbfI NLQAASAD IGARGLQV(SEQ ID NO: (SEQ ID NO: 250) 251) SEQ ID NO: 5 RYSE 5 24 70.8 29.2 71.2AsiSI NAIADAAD IGGVGDRV (SEQ ID NO: (SEQ ID NO: 252) 253) SEQ ID NO: 6RYSE 6 24 70.8 29.2 70.9 NotI KAAAGEGD ISLASGRL (SEQ ID NO: (SEQ ID NO:254) 255) SEQ ID NO: 7 RYSE 7 24 70.8 29.2 71.5 AscI KARHGRRD (SEQ IDNO: 256) SEQ ID NO: 8 RYSE 8 24 75.0 25.0 70.7 BbvCI SEQ ID NO: 9 RYSE 936 50.0 50.0 67.4 SEQ ID NO: 10 RYSE 10 36 52.8 47.2 67.7 SEQ ID NO: 11RYSE 11 36 58.3 41.7 69.2 SEQ ID NO: 12 RYSE 12 36 50.0 50.0 67.4 SEQ IDNO: 13 RYSE 13 36 58.3 41.7 69.4 SEQ ID NO: 14 RYSE 14 36 52.8 47.2 67.4SEQ ID NO: 15 RYSE 15 36 52.8 47.2 67.8 SEQ ID NO: 16 RYSE 16 36 52.847.2 67.8 SEQ ID NO: 17 RYSE 17 36 52.8 47.2 68.4 SEQ ID NO: 18 RYSE 1836 50.0 50.0 67.8 SEQ ID NO: 19 RYSE 19 36 52.8 47.2 68.1 SEQ ID NO: 20RYSE 20 36 55.6 44.4 68.3 SEQ ID NO: 21 RYSE 21 36 55.6 44.4 67.9 SEQ IDNO: 22 RYSE 22 36 52.8 47.2 67.4 SEQ ID NO: 23 RYSE 23 36 55.6 44.4 68.8

5.8 Libraries

In another aspect, provided herein is a library comprising a pluralityof assembly vectors. The library can serve to facilitate the efficientassembly of a plurality of component polynucleotides into one or moreassembled polynucleotides that are functional in prokaryotes oreukaryotes, and thus facilitate the generation of unique organisms, e,g,recombinant strains of bacteria or yeast, without the need fortime-consuming restriction endonuclease and ligase enzyme based cloningtechniques. The assembly methods and compositions provided herein canfacilitate the efficient replacement or introduction of functional DNAunits, e.g., promoters, enhancers, origins of replication, etc., withinan expression construct, and thus can provide for efficient optimizationof the replication of, and/or expression from, the expression constructwithin a host organism.

The library may comprise a plurality of assembly vectors assembledwithin a single composition or container, e.g., a composition orcontainer suitable for performing the assembly methods provided herein.Alternatively, the library may comprise a plurality of assembly vectorsthat are not assembled within the same composition or container. In someembodiments, the library comprises at least 3, at least 6, at least 10,at least 20, at least 50, or more than 50 assembly vectors, eachcomprising a DNA segment.

In some embodiments, the library comprises a plurality of assemblyvectors wherein each of the assembly vectors comprises, in a 5′ to 3′orientation, a first restriction site RA, a DNA segment D, an annealablelinker sequence LB, and a second restriction site RB. In someembodiments, the library comprises a plurality of assembly vectorswherein each of the assembly vectors comprises, in a 5′ to 3′orientation, a first restriction site RA, a primer binding segment PA ora first annealable linker sequence LA, a DNA segment D, and a secondrestriction site RB. In some embodiments, the library comprises aplurality of assembly vectors wherein each of the assembly vectorscomprises, in a 5′ to 3′ orientation, a first restriction site RA, afirst annealable linker sequence LA, a DNA segment D, an annealablelinker sequence LB or a primer binding segment PB, and a secondrestriction site RB. In some embodiments, the annealable linker sequencepair or annealable linker sequence/primary binding segment pair withineach assembly vector of the library does not comprise the same sequence.In some embodiments, the nucleic acid sequence of the annealable linkersequence LA and/or LB within each assembly vector is selected from thegroup consisting of SEQ ID NOS: 1 to 23. In some embodiments, thenucleic acid sequence of the primer binding segment PA or PB within eachassembly vector is selected from the group consisting of SEQ ID NOS: 24and 25.

In some embodiments, the library comprises at least one of each of thefollowing vectors:

-   -   (a) a vector that consists of a circular polynucleotide that        comprises, in a 5′ to 3′ orientation, a restriction site RA, a        DNA segment D, an annealable linker sequence LB, and a        restriction site RB;    -   (b) a vector that consists of a circular polynucleotide that        comprises, in a 5′ to 3′ orientation, a restriction site RA, an        annealable linker sequence LA, a DNA segment D, an annealable        linker sequence LB, and a restriction site RB; and    -   (c) a vector that consists of a circular polynucleotide that        comprises, in a 5′ to 3′ orientation, a restriction site RA, an        annealable linker sequence LA, a DNA segment D, and a        restriction site RB₀.

In some embodiments, the library comprises at least one of each of thefollowing vectors:

(a) a vector that consists of a circular polynucleotide that comprises,in a 5′ to 3′ orientation, a restriction site RA, a primer bindingsegment PA, a DNA segment D, an annealable linker sequence LB, and arestriction site RB;

(b) a vector that consists of a circular polynucleotide that comprises,in a 5′ to 3′ orientation, a restriction site RA, an annealable linkersequence LA, a DNA segment D, an annealable linker sequence LB, and arestriction site RB; and

(c) a vector that consists of a circular polynucleotide that comprises,in a 5′ to 3′ orientation, a restriction site RA, an annealable linkersequence LA, a DNA segment D, a primer binding segment PB, and arestriction site RB₀.

In some embodiments, the nucleic acid sequence of primer binding segmentPA is selected from the group consisting of SEQ ID NOS: 24 and 25. Insome embodiments, the nucleic acid sequence of primer binding segment PBis selected from the group consisting of SEQ ID NOS: 24 and 25. In someembodiments, the nucleic acid sequences of primer binding segment PA andprimer binding segment PB are selected from the group consisting of SEQID NOS: 24 and 25.

In some embodiments, the nucleic acid sequence of any of the annealablelinker sequences LA and annealable linker sequences LB in the libraryare selected from the group consisting of SEQ ID NOS: 1 to 23. In someembodiments, the nucleic acid sequences of at least one of theannealable linker sequences LA and at least one of the annealable linkersequences LB in the library are selected from the group consisting ofSEQ ID NOS: 1 to 23. In some embodiments, the nucleic acid sequence ofeach of the annealable linker sequences LA and annealable linkersequences LB in the library is selected from the group consisting of SEQID NOS: 1 to 23.

In some embodiments, the DNA segment D comprises a nucleic sequenceselected from the group consisting of a selectable marker, a promoter, agenomic targeting sequence, a nucleic acid sequence encoding an epitopetag, a nucleic acid sequence encoding a gene of interest, a nucleic acidsequence encoding a termination codon, and lacZ.

In some embodiments, the library comprises at least one of each of thefollowing nucleic acid molecules:

-   -   (a) a first nucleic acid molecule wherein the first nucleic acid        molecule is circular and comprises, in a 5′ to 3′ orientation, a        first restriction site RA₀, any DNA segment selected from the        group D₀, an annealable linker sequence LB₀, and a second        restriction site RB₀;    -   (b) an intermediate nucleic acid molecule wherein the        intermediate nucleic acid molecule n is circular and comprises,        in a 5′ to 3′ orientation, a first restriction site RA_(n), a        first annealable linker sequence LA_(n), any DNA segment        selected from the group D_(n), a second annealable linker        sequence LB_(n), and a second restriction site RB_(n), and        wherein n represents an integer from one to the number of        intermediate nucleic acid molecules; and    -   (c) a last nucleic acid molecule wherein the last nucleic acid        molecule is circular and comprises, in a 5′ to 3′ orientation, a        first restriction site RA_(m), an annealable linker sequence        LA_(m), any DNA segment selected from the group D_(m), a second        restriction site RB_(m) wherein m represents an integer one        greater than the number of intermediate nucleic acid molecules;        whereupon cleavage of restriction sites RA₀ through RB_(m) and        denaturation of the resulting linear nucleic acid molecules,        each annealable linker sequence LB_((p-1)) is capable of        hybridizing to the complement of annealable linker sequence        LA_(p) wherein p represents the integers from 1 to m, and        wherein each group D₀, . . . D_(n), . . . and D_(m) consists of        one or more DNA segments. In some embodiments, a first nucleic        acid molecule further comprises a primer binding segment PA        positioned 5′ to the DNA segment selected from the group D₀. In        some embodiments, a last nucleic acid molecules further        comprises a primer binding segment PB positioned 3′ to the DNA        segment selected from the group D_(m).

In some embodiments, upon cleavage of restriction sites RA₀ throughRB_(m) and denaturation of the resulting linear nucleic acid molecules,each annealable linker sequence LB_((p-1)) is capable of selectivelyhybridizing to the complement of annealable linker sequence LA_(p)compared to the other annealable linker sequences, or their complements,in the components composition. In some embodiments, each annealablelinker sequence LB_((p-1)) is identical in sequence to annealable linkersequence LA_(p).

In a particular embodiment, the restriction sites RA₀ through RB_(m) arecleavable by the same restriction endonuclease so as to facilitateexcision of the component polynucleotides from the assembly vectors. Insome embodiments, the restrictions sites RA₀ through RB_(m) arecleavable by SapI and LguI restriction endonucleases.

In some embodiments, the nucleic acid sequence of primer binding segmentPA is selected from the group consisting of SEQ ID NOS: 24 and 25. Insome embodiments, the nucleic acid sequence of primer binding segment PBis selected from the group consisting of SEQ ID NOS: 24 and 25. In someembodiments, the nucleic acid sequences of primer binding segment PA andprimer binding segment PB are selected from the group consisting of SEQID NOS: 24 and 25. In preferable embodiments, the nucleic acid sequencesof primer binding segment PA and primer binding segment PB are notidentical.

In some embodiments, the nucleic acid sequence of any of the annealablelinker sequences LA and annealable linker sequences LB in the library isselected from the group consisting of SEQ ID NOS: 1 to 23. In someembodiments, the nucleic acid sequences of at least one of theannealable linker sequences LA and at least one of the annealable linkersequences LB in the library are selected from the group consisting ofSEQ ID NOS: 1 to 23. In some embodiments, the nucleic acid sequence ofeach of the annealable linker sequences LA and annealable linkersequences LB in the library is selected from the group consisting of SEQID NOS: 1 to 23. In some embodiments, the nucleic acid sequence of eachof the annealable linker sequences LA in the composition are notidentical to one another. In some embodiments, the nucleic acid sequenceof each of the annealable linker sequences LB in the composition are notidentical to one another.

In a particular embodiment, the library comprises the following nucleicacid molecules:

-   -   (a) two first nucleic acid molecules, wherein one first nucleic        acid molecule comprises, in a 5′ to 3′ orientation, a first        restriction site RA₀, a primer binding segment PA, a DNA segment        D₀₁, an annealable linker sequence LB₀, and a second restriction        site RB₀, wherein another first nucleic acid molecule comprises,        in a 5′ to 3′ orientation, a first restriction site RA₀, a        primer binding segment PA, a DNA segment D₀₂, an annealable        linker sequence LB₀, and a second restriction site RB₀, wherein        DNA segment D₀₁ encodes a first genomic targeting sequence,        wherein DNA segment D₀₂ encodes a second genomic targeting        sequence located downstream of the first genomic targeting        sequence in a target genome, and wherein DNA segment D₀₂ is        positioned in opposite orientation as DNA segment D₀₁ relative        to primer binding segment PA and annealable linker sequence LB₀;    -   (b) at least one intermediate nucleic acid molecule comprising,        in a 5′ to 3′ orientation, a first restriction site RA_(n), a        first annealable linker sequence LA_(n), a DNA segment D_(n), a        second annealable linker sequence LB_(n), and a second        restriction site RB_(n), wherein n represents an integer from        one to the number of intermediate nucleic acid molecules; and    -   (c) two last nucleic acid molecules, wherein one last nucleic        acid molecule comprises, in a 5′ to 3′ orientation, a first        restriction site RA_(m), an annealable linker sequence LA_(m), a        DNA segment D_(m1), a primer binding segment PB, and a second        restriction site RB_(m), wherein another last nucleic acid        molecule comprises, in a 5′ to 3′ orientation, a first        restriction site RA_(m), an annealable linker sequence LA_(m), a        DNA segment D_(m2), a primer binding segment PB, and a second        restriction site RB_(m), wherein m represents an integer one        greater than the number of intermediate nucleic acid molecules,        wherein DNA segment D_(m1) encodes a first segment of a        selectable marker, wherein DNA segment D_(m2) encodes a second        segment of the selectable marker, wherein DNA segment D_(m2) is        positioned in opposite orientation as DNA segment D_(m1)        relative to annealable linker sequence LA_(m) and primer binding        segment PB, wherein neither DNA segment D_(m1) nor DNA segment        D_(m2) produces a functional selectable marker but whereupon        homologous recombination of DNA segments D_(m1) and D_(m2) a        functional selectable marker is generated;        wherein each annealable linker sequence LB_((p-1)) is identical        to annealable linker sequence LA_(p), wherein p represents the        integers from 1 to m.

In some embodiments, the library comprises a plurality of assemblyvectors wherein each assembly vector comprises the same annealablelinker sequence, annealable linker sequence pair or annealable linkersequence/primary binding segment pair but differs in the sequence oftheir respective DNA fragment D.

In other embodiments, the library comprises a plurality of assemblyvectors wherein each assembly vector comprises the same DNA segment Dflanked by a unique annealable linker sequence, annealable linkersequence pair or annealable linker sequence/primer binding segment pair.Such a library may serve to facilitate the rapid assembly of DNA segmentD into a particular position or orientation relative to the other DNAsegments being assembled into the assembled polynucleotide.

In some embodiments, the members of the library comprise DNA segmentsthat have shared structural or functional characteristics. For example,a library can comprise a plurality of assembly vectors comprising thesame functional DNA unit. Exemplary functional DNA units include but arenot limited to protein-coding sequences, reporter genes, fluorescentmarkers, promoters, enhancers, terminators, introns, exons, poly-Atails, multiple cloning sites, nuclear localization signals, nuclearexport signals, mRNA stabilization signals, selectable markers,integration loci, epitope tags, and degradation signals. In someembodiments, the library comprises a plurality of assembly vectorswherein each assembly vector comprises the same promoter. The assemblyvectors can comprise any prokaryotic or eukaryotic promoter sequenceknown in the art. Exemplary eukaryotic promoters include but are notlimited to a metallothionein promoter, a constitutive adenovirus majorlate promoter, a dexamethasone-inducible MMTV promoter, a SV40 promoter,a MRP pol III promoter, a constitutive MPSV promoter, an RSV promoter, atetracycline-inducible CMV promoter (such as the human immediate-earlyCMV promoter), and a constitutive CMV promoter. In particularembodiments, the assembly vectors comprise a yeast promoter sequence.Exemplary yeast promoters include but are not limited to PGAL3, PGAL7,PCTR3, PMET3, PPGK1, PTDH1, PTDH3, PFBA1, PTEF1, PENO1, PENO2, PCYC1,PTDH2, PCUP1, PGAL80, PGAL2, PBNA6, PTMA29, PSBP1, PPUP3, PACS2, PTPO1,PRPT1, PAAT2, PAHP1, PSSE1, PTEF2, PNPL3, PPET9, PTUB2, POLE1, PCPR1,PIPPP1, and PSOD1.

In some embodiments, the library comprises a plurality of assemblyvectors wherein each assembly vector comprises the same terminatorsequence. The assembly vectors can comprise any prokaryotic oreukaryotic terminator sequence known in the art. In particularembodiments, the assembly vectors comprise a yeast terminator sequence.Exemplary yeast terminators include but are not limited to TADH1, TENO1,TENO2, TCYC1, TNDT80, TTDH3, TTDH1, and TPGK1.

In some embodiments, the library comprises a plurality of assemblyvectors wherein each assembly vector comprises the same selectablemarker. The assembly vectors can comprise any prokaryotic or eukaryoticselectable marker known in the art. Examples of selectable markersinclude but are not limited to antibiotic resistance markers (e.g.,genes encoding resistance to kanamycin, ampicillin, chloramphenicol,gentamycin, or trimethoprim) and metabolic markers (e.g., amino acidsynthesis genes or transfer RNA genes).

5.9 Kits

In another aspect, provided herein is a kit for the assembly of apolynucleotide, said kit comprising two or more of the following: (a)one or more entry vectors described herein; (b) one or more restrictionendonucleases capable of cleaving the restriction sites RA and RB ofsaid one or more entry vectors; (c) one or more restrictionendonucleases capable of cleaving the restriction sites RY and RZ ofsaid entry vectors; and (d) oligonucleotide primers capable of annealingto primer binding segments PA and PB of said one or more entry vectors.

In some embodiments, restriction sites RA and RB of each entry vector ofthe kit are recognizable and cleavable by SapI restriction endonuclease,and the kit comprises SapI restriction endonuclease. In someembodiments, restriction sites RY and RZ of each entry vector of the kitare recognizable and cleavable by SchI (or MlyI) restrictionendonuclease, and the kit comprises SchI (or MlyI) restrictionendonuclease.

In some embodiments, the nucleic acid sequence of primer binding segmentPA of one or more entry vectors in the kit is selected from the groupconsisting of SEQ ID NOS: 24 and 25. In some embodiments, the nucleicacid sequence of primer binding segment PB one or more entry vectors inthe kit is selected from the group consisting of SEQ ID NOS: 24 and 25.In preferable embodiments, the nucleic acid sequences of primer bindingsegment PA and primer binding segment PB are not identical.

In some embodiments, the nucleic sequence of annealable linker sequenceLA of one or more entry vectors in the kit is selected from the groupconsisting of SEQ ID NOS: 1 to 23. In some embodiments, the nucleicsequence of annealable linker sequence LB one or more entry vectors inthe kit is selected from the group consisting of SEQ ID NOS: 1 to 23. Insome embodiments, the nucleic sequences of annealable linker sequence LAand annealable linker sequence LB of all the entry vectors in the kitare selected from the group consisting of SEQ ID NOS: 1 to 23.

In some embodiments, the kit comprises pRYSE vector #1, the sequence ofwhich is provided herein as SEQ ID NO: 221. In some embodiments, the kitcomprises pRYSE vector #2, the sequence of which is provided herein asSEQ ID NO: 207. In some embodiments, the kit comprises pRYSE vector #3,the sequence of which is provided herein as SEQ ID NO: 208. In someembodiments, the kit comprises pRYSE vector #4, the sequence of which isprovided herein as SEQ ID NO: 209. In some embodiments, the kitcomprises pRYSE vector #5, the sequence of which is provided herein asSEQ ID NO: 210. In some embodiments, the kit comprises pRYSE vector #6,the sequence of which is provided herein as SEQ ID NO: 211. In someembodiments, the kit comprises pRYSE vector #7, the sequence of which isprovided herein as SEQ ID NO:212. In some embodiments, the kit comprisespRYSE vector #8, the sequence of which is provided herein as SEQ ID NO:213. In some embodiments, the kit comprises pRYSE vector #9, thesequence of which is provided herein as SEQ ID NO: 214. In someembodiments, the kit comprises pRYSE vector #10, the sequence of whichis provided herein as SEQ ID NO: 215. In some embodiments, the kitcomprises pRYSE vector #11, the sequence of which is provided herein asSEQ ID NO: 216. In some embodiments, the kit comprises pRYSE vector #12,the sequence of which is provided herein as SEQ ID NO: 217. In someembodiments, the kit comprises pRYSE vector #13, the sequence of whichis provided herein as SEQ ID NO: 218. In some embodiments, the kitcomprises pRYSE vector #14, the sequence of which is provided herein asSEQ ID NO:219. In some embodiments, the kit comprises pRYSE vector #15,the sequence of which is provided herein as SEQ ID NO: 220.

In some embodiments, the kit further comprises instructions for use thatdescribe the polynucleotide assembly method disclosed herein. In someembodiments, a polynucleotide polymerase, such as a thermostable DNApolymerase (e.g., Pfu DNA polymerase), and deoxyribonucleosidetriphosphates (dNTPs) are also present in the kit. In some embodiments,two or more assembly vectors each comprising a component polynucleotideto be assembled into an assembled polynucleotide may be provided in thekit. For example, assembly vectors may be provided that comprise acomponent polynucleotide useful for calibration and/or for use as apositive control to verify correct performance of the kit. Otherexamples include but are not limited to assembly vectors comprising as acomponent polynucleotide a protein-coding sequence, reporter gene,fluorescent marker coding sequence, promoter, enhancer, terminator,intron, exon, poly-A tail, multiple cloning site, nuclear localizationsignal, mRNA stabilization signal, selectable marker, integration loci,epitope tag coding sequence, and degradation signal.

6. EXAMPLES

The invention is illustrated by the following examples, which are notintended to be limiting in any way. The Saccharomyces cerevisiaeconstructs described in the Examples were derived from Saccharomycescerevisiae strain CEN.PK2. Unlike Saccharomyces cerevisiae strain S288c,the genomic sequence of strain CEN.PK2 is not publicly available. Someof the constructs described were sequence-verified, and so the sequencesprovided are those of the actual CEN.PK2-derived constructs. Forconstructs that were not sequence-verified, the sequences provided arebased on the published genomic sequence of strain S288c, and thus mayinclude polymorphic differences to the sequences of the actualCEN.PK2-derived constructs.

Example 1

This example describes methods for making pRYSE vectors. pRYSE vectorscomprise, in a 5′ to 3′ orientation, a first SapI restriction enzymerecognition site, a first annealable linker sequence or primer bindingsegment, a first SchI restriction enzyme recognition site, a greenfluorescent protein (GFP) or lacZ marker gene, a second SchI restrictionenzyme recognition site, a second annealable linker sequence or primerbinding segment, and a second SapI restriction enzyme recognition site.

A DNA fragment encoding β-lactamase was PCR amplified from the pUC19vector (GenBank accession L09137) using primers JCB158-17C (SEQ ID NO:229) and JCB158-17D (SEQ ID NO: 230) after the SchI restriction enzymerecognition site in the bla gene of pUC19 had been removed bysite-directed mutagenesis of pUC19 using PCR primers JCB158-17A (SEQ IDNO: 227) and JCB158-17B (SEQ ID NO: 228). The PCR product was gelpurified, and then ligated into the TOPO vector (Invitrogen, Carlsbad,Calif.), from which it was liberated again by digesting the construct tocompletion using SphI and MfeI restriction enzymes, yielding the “blaDNA fragment”.

DNA fragments 1040 (SEQ ID NO: 224), 1041 (SEQ ID NO: 225), and 1042(SEQ ID NO: 226) were generated synthetically (Biosearch Technologies,Novato, Calif.). DNA fragments 1040 and 1041 were digested to completionusing BstXI restriction enzyme, and each digested fragment was ligatedwith the 2.65 kb vector backbone that was generated by cutting tocompletion pAM1466 (SEQ ID NO: 223; generated synthetically by BiosearchTechnologies, Novato, Calif.) using restriction enzymes SacI and KpnI.The 1040_pAM1466 DNA construct was digested to completion using BsmBIand BstXI restriction enzymes, the reaction mixture was resolved by gelelectrophoresis, and an approximately 3.5 kb DNA fragment comprising the1040 DNA fragment was gel purified. The 1041_pAM1466 DNA construct wasdigested to completion using BsaI and BstXI restriction enzymes, thereaction mixture was resolved by gel electrophoresis, and anapproximately 0.9 kb 1041 DNA fragment comprising the 1041 DNA fragmentwas gel purified. The purified DNA fragments were ligated, yielding DNAconstruct 1040_(—)1041_pAM1466. DNA fragment 1042 was joined to DNAconstruct 1040_(—)1041 by a PCR “stitching” reaction using primers JO36(SEQ ID NO: 69) and JO37 (SEQ ID NO: 70) to generate the 1040_(—)1041DNA fragment, primers JO38 (SEQ ID NO: 71) and JO39 (SEQ ID NO: 72) togenerate the 1042 DNA fragment with a terminal sequence that overlappeda terminal sequence of the 1040_(—)1041 DNA fragment, and primers JO39(containing a SphI restriction enzyme recognition site) (SEQ ID NO: 72)and JO36 (containing a MfeI restriction enzyme recognition site) (SEQ IDNO: 69) to join the two PCR products. The 1040_(—)1041_(—)1042 PCRproduct was digested to completion using SphI and MfeI restrictionenzymes, the reaction mixture was resolved by gel electrophoresis, theapproximately 2.4 kb 1040_(—)1041_(—)1042 DNA fragment was gel purified,and the purified DNA fragment was ligated to the gel purified blafragment, yielding the “1040_(—)1041_(—)1042_bla” DNA construct.

The segment of the 1040_(—)1041_(—)1042 bla DNA construct encoding theGFP gene was PCR amplified using PCR primers 1 and 2 (see Table 2). Tothe amplified GFP fragment terminal SacI and XhoI restriction enzymesrecognition sites were added by PCR amplification using as templates thegel-extracted GFP fragments generated in the first round of PCRreactions, and PCR primers 3 and 4 (see Table 2). The amplified PCRproducts were gel extracted, then digested to completion using XhoI andSacI restriction enzymes, the restriction enzymes were heat inactivatedfor 20 minutes at 65° C., and the digested PCR products were columnpurified and then ligated with the gel purified approximately 2.2 kb DNAfragment that resulted from digesting the 1040_(—)1041_(—)1042 bla DNAconstruct to completion using XhoI and SacI restriction enzymes. Theresulting vectors were PCR amplified using PCR primers 5 and 6 (seeTable 3), the reaction mixtures were resolved by gel electrophoresis,and the approximately 2.2 kb “pRYSE vector backbones” were gel purified.

TABLE 2 PCR Primers used to Generate GFP Inserts Flanked by AnnealableLinker Pairs or Annealable Linker/Primer Binding Segment Pairs and SacIand XhoI Restriction Enzyme Sites Annealable Annealable Linker or Linkeror Primer Primer GFP Binding Binding Fragment Segment 1 Segment 2 Primer1 Primer 2 Primer 3 Primer 4 1 Pme1-5′ RYSE 1 J018 J073 J055 J064 (SEQID (SEQ ID NO: (SEQ ID (SEQ ID NO: 73) 106) NO: 88) NO: 97) 2 RYSE 1RYSE 2 J019 J074 J056 J065 (SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 74)107) NO: 89) NO: 98) 3 RYSE 2 RYSE 3 J020 J029 J057 J066 (SEQ ID (SEQ IDNO: (SEQ ID (SEQ ID NO: 75) 82) NO: 90) NO: 99) 4 RYSE 3 RYSE 4 J021J030 J058 J067 (SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 76) 83) NO: 91)NO: 100) 5 RYSE 4 RYSE 5 J022 J031 J059 J068 (SEQ ID (SEQ ID NO: (SEQ ID(SEQ ID NO: 77) 84) NO: 92) NO: 101) 6 RYSE 5 RYSE 6 J023 J032 J060 J069(SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 78) 85) NO: 93) NO: 102) 7 RYSE6 RYSE 7 J024 J033 J061 J070 (SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 79)86) NO: 94) NO: 103) 8 RYSE 7 RYSE 8 J025 J034 J062 J071 (SEQ ID (SEQ IDNO: (SEQ ID (SEQ ID NO: 80) 87) NO: 95) NO: 104) 9 RYSE 2 Pme1-3′ J020J075 J057 J072 (SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 75) 108) NO: 90)NO: 105) 10 RYSE 3 Pme1-3′ J021 J075 J058 J072 (SEQ ID (SEQ ID NO: (SEQID (SEQ ID NO: 76) 108) NO: 91) NO: 105) 11 RYSE 4 Pme1-3′ J022 J075J059 J072 (SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 77) 108) NO: 92) NO:105) 12 RYSE 5 Pme1-3′ J023 J075 J060 J072 (SEQ ID (SEQ ID NO: (SEQ ID(SEQ ID NO: 78) 108) NO: 93) NO: 105) 13 RYSE 6 Pme1-3′ J024 J075 J061J072 (SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 79) 108) NO: 94) NO: 105)14 RYSE 7 Pme1-3′ J025 J075 J062 J072 (SEQ ID (SEQ ID NO: (SEQ ID (SEQID NO: 80) 108) NO: 95) NO: 105) 15 RYSE 8 Pme1-3′ J026 J075 J063 J072(SEQ ID (SEQ ID NO: (SEQ ID (SEQ ID NO: 81) 108) NO: 96) NO: 105)

TABLE 3 Annealable Linker Sequence Pairs or Annealable LinkerSequnece/Primer Binding Segment Pairs Present in pRYSE Vectors, and PCRPrimers Used to Generate pRYSE Vector Backbones Annealable AnnealableLinker or Linker or Primer Primer Binding Binding Segment 1 Segment 2(see Table (see Table pRYSE vector 1) 1) Primer 5 Primer 6 1 Pme1-5′RYSE 1 S001 (SEQ ID NO: S002 (SEQ ID NO: 46) 47) 2 RYSE 1 RYSE 2 S003(SEQ ID NO: S004 (SEQ ID NO: 48) 49) 3 RYSE 2 RYSE 3 S005 (SEQ ID NO:S006 (SEQ ID NO: 50) 51) 4 RYSE 3 RYSE 4 S007 (SEQ ID NO: S008 (SEQ IDNO: 52) 53) 5 RYSE 4 RYSE 5 S009 (SEQ ID NO: S010 (SEQ ID NO: 54) 55) 6RYSE 5 RYSE 6 S011 (SEQ ID NO: S012 (SEQ ID NO: 56) 57) 7 RYSE 6 RYSE 7S013 (SEQ ID NO: S014 (SEQ ID NO: 58) 59) 8 RYSE 7 RYSE 8 S015 (SEQ IDNO: S016 (SEQ ID NO: 60) 61) 9 RYSE 2 Pme1-3′ S005 (SEQ ID NO: S018 (SEQID NO: 50) 63) 10 RYSE 3 Pme1-3′ S007 (SEQ ID NO: S018 (SEQ ID NO: 52)63) 11 RYSE 4 Pme1-3′ S009 (SEQ ID NO: S018 (SEQ ID NO: 54) 63) 12 RYSE5 Pme1-3′ S011 (SEQ ID NO: S018 (SEQ ID NO: 56) 63) 13 RYSE 6 Pme1-3′S013 (SEQ ID NO: S018 (SEQ ID NO: 58) 63) 14 RYSE 7 Pme1-3′ S015 (SEQ IDNO: S018 (SEQ ID NO: 60) 63) 15 RYSE 8 Pme1-3′ S017 (SEQ ID NO: S018(SEQ ID NO: 62) 63)

The lacZ gene was PCR amplified from the pUC19 vector using primers S027(SEQ ID NO: 65) and S028 (SEQ ID NO: 66), which each comprise a SchIrestriction enzyme recognition site. The reaction mixture was resolvedby gel electrophoresis, the approximately 0.5 kb PCR product was gelpurified, and the purified PCR product was ligated with each of thepRYSE vector backbones. Site-directed mutagenesis was performed on theresulting vectors using PCR primers L012 (SEQ ID NO: 231) and L013 (SEQID NO: 232) to remove a SchI restriction enzyme recognition site fromthe origin of replication. Finally, a second site-directed mutagenesiswas performed using PCR primers 5036 (SEQ ID NO: 67) and S037 (SEQ IDNO: 68) to remove the SchI restriction enzyme recognition site from thelacZ fragment, thus yielding pRYSE vectors 1 through 15 (see FIG. 4 fora plasmid map of the pRYSE vectors, and SEQ ID NOS: 207 through 221 forthe nucleotide sequence of pRYSE vectors 1 through 15).

Example 2

This example describes alternative methods for making pRYSE vectors.

pRYSE vectors 1 through 15 can be generated synthetically using astemplate SEQ ID NOS: 207 through 221 (e.g., by Biosearch Technologies,Novato, Calif.). Additional pRYSE vectors comprising differentannealable linker sequences can be generated synthetically using astemplate SEQ ID NO: 221 in which the Pme1-5′ primer binding segmentand/or the RYSE 1 annealable linker sequence are changed to anothersuitable annealable linker sequence or primer binding segment (see Table1).

Example 3

This example describes methods for making a pMULE vector, comprising, ina 5′ to 3′ orientation, a first SapI restriction enzyme recognitionsite, a first SchI restriction enzyme recognition site, a lacZ markergene, a second SchI restriction enzyme recognition site, and a secondSapI restriction enzyme recognition site. The pMULE vector can be usedto clone Mules.

The backbone of pRYSE vector 8 was PCR amplified using primers K162 (SEQID NO: 109) and K163 (SEQ ID NO: 110). The reaction mixture was resolvedby gel electrophoresis, and the approximately 2.2 kb vector backbone wasgel purified. A DNA fragment comprising the lacZ gene was generated bydigesting to completion pRYSE vector 8 using SchI restriction enzyme,heat inactivating the enzyme at 65° C. for 20 minutes, resolving thereaction mixture by gel electrophoresis, and gel purifying theapproximately 0.5 kb DNA fragment. The purified DNA fragment comprisingthe lacZ gene was ligated with the purified vector backbone, yieldingthe pMULE vector (see FIG. 7 for a plasmid map).

Example 4

This example describes methods for making “Bits”. Bits are DNA fragmentsthat can be inserted into pRYSE vectors to generate assembly vectorscomprising component polynucleotides that can be assembled intoassembled polynucleotides using methods disclosed herein. Bits mayencode genes or genetic elements of interest (e.g., promoters,terminators, selectable markers, integration loci, epitope tags,localization signals, degradation signals, fluorescent markers, multiplecloning sites). Bits were PCR amplified from a template using primers asdescribed in Table 4.

TABLE 4 Amplified Bits Size Bit Type* Primers (bp) Template atoB Gs L229(SEQ ID NO: 40) 1185 plasmid DNA comprising the atoB L230 (SEQ ID NO:41) gene from Escherichia coli (GenBank accession number NC_000913REGION: 2324131 . . . 2325315) mvaS Gs L235 (SEQ ID NO: 42) 1152synthetic DNA fragment comprising L236 (SEQ ID NO: 43) mvaS gene fromEnter° C.°Ccus faecalis (GenBank accession number AF290092 REGION: 142 .. . 1293) codon-optimized for expression in Saccharomyces cerevisiae andcomprising at position 110 an alanine to glycine modification toincrease enzyme activity (see Steussy et al. (2006) Bi°Chemistry 45(48):14407-14414) ERG13-1 GsT L109 (SEQ ID NO: 235) 1726 Saccharomycescerevisiae strain L110 (SEQ ID NO: 26) CEN.PK2 genomic DNA 3′ D L221(SEQ ID NO: 34) 516 Saccharomyces cerevisiae strain NDT80 L222 (SEQ IDNO: 35) CEN.PK2 genomic DNA 5′ U L219 (SEQ ID NO: 32) 495 Saccharomycescerevisiae strain NDT80 L220 (SEQ ID NO: 33) CEN.PK2 genomic DNAtP_(FBA1) P L225 (SEQ ID NO: 37) 526 Saccharomyces cerevisiae strainL057 (SEQ ID NO: 234) CEN.PK2 genomic DNA tP_(TDH3) P L224 (SEQ ID NO:36) 559 Saccharomyces cerevisiae strain L054 (SEQ ID NO: 233) CEN.PK2genomic DNA ERG10-1 Gs L226 (SEQ ID NO: 38) 1182 synthesized fragmentencoding the L227 (SEQ ID NO: 39) acetyl-CoA acetyltransferase ofRalstonia eutropha (GenBank accession NC_008313 REGION: 183291 . . .184469) codon-optimized for expression in Saccharomyces cerevisiae andfollowed by an additional stop codon tENO1 T L248 (SEQ ID NO: 44) 265Saccharomyces cerevisiae strain L176 (SEQ ID NO: 27) CEN.PK2 genomic DNAtTDH3 T L185 (SEQ ID NO: 28) 260 Saccharomyces cerevisiae strain L186(SEQ ID NO: 29) CEN.PK2 genomic DNA HphA M TRIX_L_193 (SEQ ID 1912plasmid DNA comprising the TEF1 NO: 184) promoter and terminator ofTRIX_L_194 (SEQ ID Kluyveromyces lactis (GenBank NO: 185) accessionCR382122 REGIONS: 788874 . . . 789380 and 787141 . . . 787496,respectively) and the hph gene of Klebsiella pneumonia tHMG1 GsTTRIX_L_232 (SEQ ID 1742 Saccharomyces cerevisiae strain NO: 186) CEN.PK2genomic DNA TRIX_L_233 (SEQ ID NO: 187) tP_(GAL1,10) P TRIX_L_266 (SEQID 620 Saccharomyces cerevisiae strain NO: 190) CEN.PK2 genomic DNATRIX_L_267 (SEQ ID NO: 191) ERG10-2 GsT TRIX_L_106 (SEQ ID 1467Saccharomyces cerevisiae strain NO: 170) CEN.PK2 genomic DNA TRIX_L_107(SEQ ID NO: 171) ERG13-2 GsT TRIX_L_109 (SEQ ID 1726 Saccharomycescerevisiae strain NO: 172) CEN.PK2 genomic DNA TRIX_L_110 (SEQ ID NO:173) GAL80US U JU-218-168-130- 500 Saccharomyces cerevisiae strainGAL80US-F (SEQ ID NO: CEN.PK2 genomic DNA 134) JU-219-168-130- GAL80US-R(SEQ ID NO: 135) GAL80DS D JU-220-168-130- 500 Saccharomyces cerevisiaestrain GAL80DS-F (SEQ ID NO: CEN.PK2 genomic DNA 136) JU-221-168-130-GAL80DS-R (SEQ ID NO: 137) P_(TDH3) P L224 (SEQ ID NO: 36) 583Saccharomyces cerevisiae strain TRIX_L_053 (SEQ ID CEN.PK2 genomic DNANO: 169) NatA M TRIX_L_193 (SEQ ID 1456 plasmid DNA comprising the TEF1NO: 184) promoter and terminator of TRIX_L_194 (SEQ ID Kluyveromyceslactis (GenBank NO: 185) accession CR382122 REGIONS: 788874 . . . 789380and 787141 . . . 787496, respectively) and the nat1 gene of S. nourseiERG12 GsT TRIX_L_112 (SEQ ID 1582 Saccharomyces cerevisiae strain NO:174) CEN.PK2 genomic DNA TRIX_L_113 (SEQ ID NO: 175) ERG8 GsT TRIX_L_118(SEQ ID 1616 Saccharomyces cerevisiae strain NO: 178) CEN.PK2 genomicDNA TRIX_L_119 (SEQ ID NO: 179) P_(GAL4oc) P TRIX_K_131 270 plasmid DNAcomprising an “operative (SEQ ID NO: 165) constitutive” version of thepromoter of PW-91-093-CPK422-G the GAL4 gene of Saccharomyces (SEQ IDNO: 162) cerevisiae strain CEN.PK2 (Griggs & Johnston (1991) PNAS88(19): 8597-8601) GAL4-1 G JU-286-275-31-GAL4-F 526 Saccharomycescerevisiae strain (SEQ ID NO: 140) CEN.PK2 genomic DNAJU-285-275-31-GAL4- FIX-R2 (SEQ ID NO: 139) GAL4-2 G JU-284-275-31-GAL4-2414 Saccharomyces cerevisiae strain FIX-F2 (SEQ ID NO: 138) CEN.PK2genomic DNA JU-287-275-31-GAL4-R (SEQ ID NO: 141) KanA M TRIX_L_193 (SEQID 1696 plasmid DNA comprising the TEF1 NO: 184) promoter and terminatorof TRIX_L_194 (SEQ ID Kluyveromyces lactis (GenBank NO: 185) accessionCR382122 REGIONS: 788874 . . . 789380 and 787141 . . . 787496,respectively) and the kanR gene of Tn903 transposon ERG19 GsT TRIX_L_115(SEQ ID 1441 Saccharomyces cerevisiae strain NO: 176) CEN.PK2 genomicDNA TRIX_L_116 (SEQ ID NO: 177) ERG20 GsT TRIX_L_124 (SEQ ID 1319Saccharomyces cerevisiae strain NO: 182) CEN.PK2 genomic DNA TRIX_L_125(SEQ ID NO: 183) P_(GAL7) P TRIX_L_34 (SEQ ID NO: 500 Saccharomycescerevisiae strain 166) CEN.PK2 genomic DNA TRIX_L_35 (SEQ ID NO: 167)tP_(GAL7) P TRIX_L_34 (SEQ ID NO: 476 Saccharomyces cerevisiae strain166) CEN.PK2 genomic DNA TRIX_L_36 (SEQ ID NO: 168) IDI1 GsT TRIX_L_121(SEQ ID 1127 Saccharomyces cerevisiae strain NO: 180) CEN.PK2 genomicDNA TRIX_L_122 (SEQ ID NO: 181) tP_(CTR3) P TRIX_K_0142 (SEQ ID 710plasmid DNA comprising promoter of NO: 163) the CTR3 gene ofSaccharomyces TRIX_K_0143 (SEQ ID cerevisiae strain CEN.PK2 NO: 164)LEU2US U JU-164-168-110-LEU2US-f 500 Saccharomyces cerevisiae strain(SEQ ID NO: 129) CEN.PK2 genomic DNA JU-165-168-110-LEU2US-r (SEQ ID NO:130) LEU2DS D JU-162-168-110-LEU2DS- 500 Saccharomyces cerevisiae strainf (SEQ ID NO: 127) CEN.PK2 genomic DNA JU-163-168-110-LEU2DS-r (SEQ IDNO: 128) ERG9US U JU-108-168-110-ERG9US-f 499 Saccharomyces cerevisiaestrain (SEQ ID NO: 126) CEN.PK2 genomic DNA JU-172-168-110-ERG9US- r1(SEQ ID NO: 133) ERG9CDS G JU-106-168-110-ERG9CDS-f 501 Saccharomycescerevisiae strain (SEQ ID NO: 124) CEN.PK2 genomic DNAJU-107-168-110-ERG9CDS-r (SEQ ID NO: 125) STE5US U TRIX_RN017 (SEQ ID600 Saccharomyces cerevisiae strain NO: 192) CEN.PK2 genomic DNATRIX_RN018 (SEQ ID NO: 193) STE5DS D TRIX_RN019 (SEQ ID 600Saccharomyces cerevisiae strain NO: 194) CEN.PK2 genomic DNA TRIX_RN020(SEQ ID NO: 195) URA3 M JU-169-168-110-URA3-f 1554 Saccharomycescerevisiae strain (SEQ ID NO: 131) CEN.PK2 genomic DNAJU-170-168-110-URA3-r (SEQ ID NO: 132) *G = gene; s = stop codon; T =terminator; M = marker; D = downstream integration region; U = upstreamintegration region; P = promoter.

PCR amplifications were done using the Phusion DNA polymerase (NewEngland Biolabs, Ipswich, Mass.) as per manufacturer's suggestedprotocol. The PCR reactions were resolved by gel electrophoresis, thebits were gel purified, and the purified bits were treated with T4polynucleotide kinase (PNK) (New England Biolabs, Ipswich, Mass.) as permanufacturer's suggested protocol. The PNK was heat inactivated at 65°C. for 20 minutes, and the samples were stored at −20° C.

Example 5

This example describes methods for making “MULEs.” MULEs are DNAfragments that can be inserted into pMULE vectors to generate assemblyvectors comprising components polynucleotides that can be assembled intoassembled polynucleotides using methods disclosed herein. MULEs mayencode genes or genetic elements of interest (e.g., promoters,terminators, selectable markers, integration loci, epitope tags,localization signals, degradation signals, fluorescent markers, multiplecloning sites) flanked by annealable linker sequence pairs or annealablelinker sequence/primer binding segment pairs. MULEs were PCR amplifiedfrom a template using primers of which the 3′ end anneals to the targetsequence and the 5′ end comprises an annealable linker sequence or aprimer binding segment (see Table 1 for suitable annealable linkersequences), as described in Table 5.

TABLE 5 Amplified MULEs Size MULE Type* Primers (bp) Template tHMG1-a GKMH8-276-1- 1794 RABit 254 plasmid DNA linker4.tHMG1.fwd (SEQ ID NO:157) KMH9-276-1-linker9.tHMG1.rev (SEQ ID NO: 160) ERG12 G KMH46-276-43-1634 RABit 250 plasmid DNA ERG12linker4.fwd (SEQ ID NO: 151)KMH14-276-4- liniker9.ERG12.rev (SEQ ID NO: 145) ERG19 G KMH47-276-43-1493 RABit 241 plasmid DNA ERG19linker4.fwd (SEQ ID NO: 152)KMH15-276-4- linker9.ERG19.rev (SEQ ID NO: 146) P_(TDH3)-a PKMH81-276-116- 626 RABit 54 plasmid DNA TDH3.rev.tHMG1 (SEQ ID NO: 155)S004 (SEQ ID NO: 49) P_(TDH3)-b P KMH91-276-116-TDH3.rev.FS 546 RABit 54plasmid DNA (SEQ ID NO: 158) S004 (SEQ ID NO: 49) tHMG1-b GKMH82-276-116- 1801 RABit 20 plasmid DNA tHMG1.fwd.TDH3 (SEQ ID NO: 156)S009 (SEQ ID NO: 54) IME1US U KB454-266-53 (SEQ ID NO: 578 Saccharomycescerevisiae strain 142) CEN.PK2 genomic DNA KB455-266-53 (SEQ ID NO: 143)IME1DS D KMH93-276-130- 554 Saccharomyces cerevisiae strain3′IME.linker4.fwd CEN.PK2 genomic DNA (SEQ ID NO: 161) KB457-266-53 (SEQID NO: 144) LEU2 M VH296-235-55-Leu2 12-1 F 1795 plasmid DNA comprisingLEU2 (SEQ ID NO: 30) locus of Saccharomyces cerevisiae VH296-235-55-Leu212-1 R strain CEN.PK2 (Sikorski RS, (SEQ ID NO: 31) Hieter (1989)Genetics 122(1): 19-27) FS-a G KMH5-276-1- 1981 plasmid DNA comprisingcoding linker3.FS(Kozak).fwd sequence of farnesene synthase of (SEQ IDNO: 153) Artemisia annua (GenBank KMH7-276-1-linker4.TCYC1.rev accessionnumber AY835398) (SEQ ID NO: 154) codon-optimized for expression inSaccharomyces cerevisiae and terminator of CYC1 gene of Saccharomycescerevisiae strain CEN.PK2 FS-b G KMH92-276-116-FS.fwd.TDH3 1976 plasmidDNA comprising coding (SEQ ID NO: 159) sequence of farnesene synthase ofKMH7-276-1-linker4.TCYC1.rev Artemisia annua (GenBank (SEQ ID NO: 154)accession number AY835398) codon-optimized for expression inSaccharomyces cerevisiae and terminator of CYC1 gene of Saccharomycescerevisiae strain CEN.PK2 URA3b M VH228-235-7- 1565 URA-3 blastertemplate** laster URA3LOF3RYSE12-1F (SEQ ID NO: 204) VH229-235-7-URA3LOF3RYSE12-1R (SEQ ID NO: 205) *G = gene; s = stop codon; T =terminator; M = marker; D = downstream integration region; U = upstreamintegration region; P = promoter. **The URA-3 blaster template was madeby first generating DNA fragments flanking sequence A (generated from asynthetic DNA fragment comprising SEQ ID NO: 206 using PCR primersTRIX_Z025 (SEQ ID NO: 196) and TRIX_Z026 (SEQ ID NO: 197)), flankingsequence B (generated from a synthetic DNA fragment comprising SEQ IDNO: 206 using PCR primers TRIX_Z027 (SEQ ID NO: 198) and TRIX_Z028 (SEQID NO: 199)), URA3-c (generated from Saccharomyces cerevisiae strainCEN.PK2 genomic DNA using PCR primers TRIX_Z033 (SEQ ID NO: 200) andTRIX_Z036 (SEQ ID NO: 203)), and URA3-d (generated from Saccharomycescerevisiae strain CEN.PK2 genomic DNA using PCR primers TRIX_Z034 (SEQID NO: 201) and TRIX_Z035 (SEQ ID NO: 202)). DNA fragments flankingsequence A, URA3-c, and URA-3-d were then stitched together into DNAfragment A using PCR primers TRIX_Z025 and TRIX_Z034, and DNA fragmentsURA3-c, URA3-d, and flanking sequence B were stitched together into DNAfragment B using PCR primers TRIX_Z028 and TRIX_Z033. Finally, DNAfragments A and B were stitched together using PCR primers TRIX_Z025 andTRIX_Z028, yielding the URA-3 blaster template.

PCR amplifications were done using the Phusion DNA polymerase (NewEngland Biolabs, Ipswich, Mass.) as per manufacturer's suggestedprotocol. The PCR reactions were resolved by gel electrophoresis, theMULEs were gel purified, and the purified MULEs were treated with T4polynucleotide kinase (PNK) (New England Biolabs, Ipswich, Mass.) as permanufacturer's suggested protocol. The PNK was heat inactivated at 65°C. for 20 minutes, and the samples were stored at −20° C.

Example 6

This example describes methods for inserting Bits into pRYSE vectors orMULEs into the pMULE vector to generate assembly vectors.

pRYSE vectors 1 through 8 and pRYSE vector 15 were digested tocompletion using SchI restriction enzyme, and the digested DNA fragmentswere treated with Antarctic Phosphatase (New England Biolabs, Ipswich,Mass.). The phosphatase was heat inactivated at 65° C. for 20 minutes,the reaction mixtures were resolved by gel electrophoresis, and theapproximately 2.2 kb pRYSE vector backbones (lacking lacZ) were gelpurified. Purified pRYSE vector backbones were ligated with Bits asdetailed in Table 6, thus yielding assembly vectors.

The pMULE vector is digested to completion using SchI restrictionenzyme, the reaction mixture is resolved by gel electrophoresis, and theapproximately 2.2 kb pMULE vector backbone (lacking lacZ) is gelpurified. The purified pMULE vector backbone is treated with aphosphatase (e.g., Antarctic Phosphatase (New England Biolabs, Ipswich,Mass.), CIAP (New England Biolabs, Ipswich, Mass.), SAP (New EnglandBiolabs, Ipswich, Mass.; Fermentas, Glen Burnie, Md.), or FastAP(Fermentas, Glen Burnie, Md.)), the phosphatase is heat inactivated(e.g., 20 min at 65° C.), and the pMULE vector backbone is ligated withMULEs, thus yielding assembly vectors.

TABLE 6 Assembly Vectors Generated pRYSE Bit Vector Assembly (see Table4) (see Table 3) Vector atoB 4 2 mvaS 7 5 ERG13-1 7 12 3′ NDT80 15 29 1024 5′ NDT80 1 30 1 97 tP_(FBA1) 6 35 tP_(TDH3) 3 53 ERG10-1 4 60 tENO1 862 tTDH3 5 64 GAL80US 1 270 HphA 2 22 tHMG1 3 254 tP_(GAL1,10) 4 229ERG10-2 5 244 ERG13-2 6 253 tP_(GAL1,10) 7 228 tHMG1 8 255 GAL80DS 15271 LEU2US 1 187 NatA 2 262 ERG12 3 250 ERG8 5 252 P_(GAL4oc) 6 268GAL4* 7 265 LEU2DS 14 263 ERG9US 1 186 KanA 2 261 ERG19 3 241 ERG20 5251 tP_(GAL7) 6 249 IDI1 7 237 tP_(CTR3) 8 269 ERG9CDS 15 185 P_(GAL7) 344 STE5US 1 567 URA3 2 556 (orientation 1) 555 (orientation 2) P_(TDH3)3 54 tHMG1 4 20 STE5DS 11 563 Ligations were performed using 50 ngvector backbone, 3 molar excess Bit, and a ligase (e.g., Quick Ligase(New England Biolabs, Ipswich, MA), T4 DNA ligase (regular and highconcentration; vendor, Fermentas, Glen Burnie, MD), Fast Ligase(Fermentas, Glen Burnie, MD)) as per manufacturer's suggested protocol.*Bit GAL4 was generated by stitching together Bits GAL4-1 and GAL4-2(see Table 4) using primers JU-286-275-31-GAL4-F (SEQ ID NO: 140) andJU-287-275-31-GAL4-R (SEQ ID NO: 141).

Assembly vectors were transformed into chemically competent TOP10Escherichia coli parent cells (Invitrogen, Carlsbad, Calif.). Host celltransformants were selected on Luria Bertoni (LB) agar containing 100ug/mL carbenicillin and 40 ug/mL X-gal. Single white colonies weretransferred from LB agar to culture tubes containing 5 mL of LB liquidmedium and carbenicillin, and the cultures were incubated overnight at37° C. on a rotary shaker at 250 rpm. Plasmid DNAs were extracted andsequenced to identify clones containing the correct sequence in thecorrect orientation. The cells were stored at −80° C. in cryo-vials in 1mL stock aliquots made up of 400 uL sterile 50% glycerol and 600 uLliquid culture.

Example 7

This example describes methods for assembling component polynucleotidesinto a assembled polynucleotide using assembly vectors and/or MULEs.

Assembly vectors (see Table 7) were placed together in one tube (333fmole of each RABit) and digested using LguI restriction enzyme(Fermentas, Glen Burnie, Md.). The restriction enzyme was removed bycolumn centrifugation or heat inactivated for 20 minutes at 65° C. Forassembly reactions involving MULEs or assembled polynucleotides, 333fmole of each MULE or assembled polynucleotide (see Table 7) were placedtogether in one tube or were added to the digested assembly vectors. Thesamples were split into three 30 uL reactions; water, buffer, dNTPs, andDNA polymerase were added to each reaction mixture, and a first round ofPCR amplification was initiated. Samples were placed on ice, 0.5 uM ofeach terminal primer (Table 7) were added to the reaction mixtures, anda second round of PCR amplification was performed. The three PCRreaction mixtures were combined in one tube, the reaction mixtures wereresolved by gel electrophoresis, and the PCR products were gel purified.

TABLE 7 Terminal Primers for Assembly of Assembled polynucleotidesAssembled Assembly Vectors (see polynucleotide Table 6) or MULEs (seeSize (kb) Terminal Terminal Assembly Table 5) To Be Combined* (Sequence)Primer 1 Primer 2 1 30_22_53_60 4.3 S000 S009 (SEQ ID NO: (SEQ ID NO:45) 54) 2 30_22_53 3.1 S000 S007 (SEQ ID NO: (SEQ ID NO: 45) 52) 322_53_60 3.7 S002 S009 (SEQ ID NO: (SEQ ID NO: 47) 54) 4 30_22 2.5 S000S005 (SEQ ID NO: (SEQ ID NO: 45) 50) 5 22_53 2.5 S002 S007 (SEQ ID NO:(SEQ ID NO: 47) 52) 6 53_60 1.8 S004 S009 (SEQ ID NO: (SEQ ID NO: 49)54) 7 30_22_53_60_64_35_12_62_29 7.7 S000 S019 (SEQ ID NO: (SEQ ID NO:(SEQ ID NO: 222) 45) 64) 8 30_22_53_60_64_35_5_62_29 7.1 S000 S019 (SEQID NO: (SEQ ID NO: 45) 64) 9 30_22_53_2_64_35_5_62_29 7.1 S000 S019 (SEQID NO: (SEQ ID NO: 45) 64) 10 60_64_35_5_62_29 4.1 S006 S019 (SEQ ID NO:(SEQ ID NO: 51) 64) 11 2_64_35_5_62_29 4.1 S006 S019 (SEQ ID NO: (SEQ IDNO: 51) 64) Phase 270_22_254_229_244_253 8.1 S000 S013 I-A (SEQ ID NO:(SEQ ID NO: (SEQ ID NO: 111) 45) 58) Phase 228_255_271 3.0 S013 S019 I-B(SEQ ID NO: (SEQ ID NO: (SEQ ID NO: 112) 58) 64) Phase187_262_250_229_252_268_265_263 9.7 S000 S019 II (SEQ ID (SEQ ID NO:(SEQ ID NO: complete NO: 113) 45) 64) Phase 186_261_241_229 4.4 S000S008 III-A (SEQ ID NO: (SEQ ID NO: (SEQ ID NO: 114) 45) 53) Phase251_249_237_269_185 4.3 S009 S018 III-B (SEQ ID NO: (SEQ ID NO: (SEQ IDNO: 115) 54) 63) Phase I 270_URA3blaster_44_FS- 6.3 S000 S019 markera_tHMG1-a (SEQ ID NO: (SEQ ID NO: (SEQ ID NO: recycling 116) 45) 64)Phase 187_URA3blaster_44_FS- 6.2 S000 S019 II a_ERG12 (SEQ ID NO: (SEQID NO: (SEQ ID NO: marker 117) 45) 64) recycling Phase186_URA3blaster_44_FS- 6.0 S000 S019 III a_ERG19 (SEQ ID NO: (SEQ ID NO:(SEQ ID NO: marker 118) 45) 64) recycling STE5 567_556_P_(TDH3)-a_tHMG1-5.2 S000 S019 knockout b_563 (SEQ ID NO: (SEQ ID NO: (SEQ ID NO: 119)45) 64) IME1 IME1US_LEU2_P_(TDH3)- 5.4 S000 S019 knockout b_FS-b_IME1DS(SEQ ID NO: (SEQ ID NO: (SEQ ID NO: 120) 45) 64) The first round of PCRamplification was performed as follows: one cycle of denature at 98° C.for 2 minutes; 5 cycles of denature at 98° C. for 30 seconds andanneal/extend at 72° C. for 30 seconds per kilobase PCR product. Thesecond round of PCR amplification was performed as follows: one cycle ofdenature at 98° C. for 2 minutes; 35 rounds of denature at 98° C. for 12seconds and anneal/extend at 72° C. for 20-25 seconds per kilobase PCRproduct; one cycle of final extend at 72° C. for 7 minutes; and a finalhold at 4° C. When the annealing temperature was not 72° C. (i.e., whenit was either 54° C. or 65° C.), in the first round of PCR amplificationa 1 minute annealing step followed by a 30 seconds per kilobase PCRproduct extension step at 72° C. was used, and for the second round ofPCR amplification a 15 seconds annealing step followed by a 20 secondsper kilobase PCR product extension step at 72° C. was used. *Assemblyvectors are designated with numbers, and MULEs with names.

As shown in FIGS. 5 and 6, 2 to 9 component polynucleotides werecorrectly assembled into up to 7.7 kb long assembled polynucleotides.

Example 8

This example describes methods for generating genetically altered hostmicroorganisms using assembled polynucleotides assembled by the methodsdisclosed herein.

Phase I-A and Phase I-B assembled polynucleotides (see Table 7) werecloned into the TOPO Zero Blunt II cloning vector (Invitrogen, Carlsbad,Calif.), yielding plasmids TOPO-Phase I-A and TOPO-Phase I-B,respectively. The constructs were propagated in TOP10 cells (Invitrogen,Carlsbad, Calif.) grown on LB agar containing 50 μg/ml kanamycin. Eachplasmid was digested to completion using NotI restriction endonuclease,the Phase I-A and Phase I-B inserts were gel extracted using a gelpurification kit (Qiagen, Valencia, Calif.), and equal molar ratios ofthe purified DNA fragments were ligated using T4 DNA ligase (New EnglandBiolabs, Ipswich, Mass.), yielding the Phase I complete assembledpolynucleotide. The Phase I complete assembled polynucleotide was clonedinto the TOPO Zero Blunt II cloning vector (Invitrogen, Carlsbad,Calif.), yielding plasmid TOPO-Phase I. The construct was propagated inTOP10 cells (Invitrogen, Carlsbad, Calif.) grown on LB agar containing50 μg/ml kanamycin.

The Phase II complete assembled polynucleotide (see Table 7) was clonedinto the TOPO Zero Blunt II cloning vector (Invitrogen, Carlsbad,Calif.), yielding plasmid TOPO-Phase II. The construct was propagated inTOP10 cells (Invitrogen, Carlsbad, Calif.) grown on LB agar containing50 μg/ml kanamycin.

The Phase III-A and Phase III-B assembled polynucleotides (see Table 7)were cloned into the TOPO Zero Blunt II cloning vector (Invitrogen,Carlsbad, Calif.), yielding plasmids TOPO-Phase III-A and TOPO-PhaseIII-B, respectively. The constructs were propagated in TOP10 cells(Invitrogen, Carlsbad, Calif.) grown on LB agar containing 50 μg/mlkanamycin. Each plasmid was digested to completion using BamHI and SbfIrestriction endonuclease, the Phase III-A and Phase III-B inserts weregel extracted using a gel purification kit (Qiagen, Valencia, Calif.),and equal molar ratios of the purified DNA fragments were ligated usingT4 DNA ligase (New England Biolabs, Ipswich, Mass.), yielding the PhaseIII complete assembled polynucleotide. The Phase III complete assembledpolynucleotide was cloned into the TOPO Zero Blunt II cloning vector(Invitrogen, Carlsbad, Calif.), yielding plasmid TOPO-Phase III. Theconstruct was propagated in TOP10 cells (Invitrogen, Carlsbad, Calif.)grown on LB agar containing 50 μg/ml kanamycin.

For yeast cell transformations, 25 ml of Yeast Extract Peptone Dextrose(YPD) medium was inoculated with a single colony of a starting hoststrain. The culture was grown overnight at 30° C. on a rotary shaker at200 rpm. The OD600 of the culture was measured, and the culture was thenused to inoculate 50 ml of YPD medium to an OD600 of 0.15. The newlyinoculated culture was grown at 30° C. on a rotary shaker at 200 rpm upto an OD600 of 0.7 to 0.9, at which point the cells were transformedwith 1 μg of DNA. The cells were allowed to recover in YPD medium for 4hours before they were plated on agar containing a selective agent toidentify the host cell transformants.

Starter host strain Y1198 was generated by resuspending active dry PE-2yeast (isolated in 1994 at Santelisa Vale, Sertãozinho, Brazil) in 5 mLof YPD medium containing 100 ug/mL carbamicillin and 50 ug/mL kanamycin.The culture was incubated overnight at 30° C. on a rotary shaker at 200rpm. An aliquot of 10 uL of the culture was then plated on a YPD plateand allowed to dry. The cells were serially streaked for singlecolonies, and incubated for 2 days at 30° C. Twelve single colonies werepicked, patched out on a new YPD plate, and allowed to grow overnight at30° C. The strain identities of the colonies were verified by analyzingtheir chromosomal sizes on a Bio-Rad CHEF DR II system (Bio-Rad,Hercules, Calif.) using the Bio-Rad CHEF Genomic DNA Plug Kit (Bio-Rad,Hercules, Calif.) according to the manufacturer's specifications. Onecolony was picked and stocked as strain Y1198.

Strains Y1661, Y1662, Y1663, and Y1664 were generated from strain Y1198by rendering the strain haploid. Strain Y1198 was grown overnight in 5mL of YPD medium at 30° C. in a glass tube in a roller drum. The OD600was measured, and the cells were diluted to an OD600 of 0.2 in 5 mL ofYP medium containing 2% potassium acetate. The culture was grownovernight at 30° C. in a glass tube in a roller drum. The OD600 wasmeasured again, and 4 OD600*mL of cells was collected by centrifugationat 5,000 g for 2 minutes. The cell pellet was washed once with sterilewater, and then resuspended in 3 mL of 2% potassium acetate containing0.02% raffinose. The cells were grown for 3 days at 30° C. in a glasstube in a roller drum. Sporulation was confirmed by microscopy. Analiquot of 33 uL of the culture was transferred to a 1.5 mL microfugetube and was centrifuged at 14,000 rpm for 2 minutes. The cell pelletwas resuspended in 50 uL of sterile water containing 2 uL of 10 mg/mLZymolyase 100T (MP Biomedicals, Solon, Ohio), and the cells wereincubated for 10 minutes in a 30° C. waterbath. The tube was transferredto ice, and 150 uL of ice cold water was added. An aliquot of 10 uL ofthis mixture was added to a 12 mL YPD plate, and tetrads were dissectedon a Singer MSM 300 dissection microscope (Singer, Somerset, UK). TheYPD plate was incubated at 30° C. for 3 days, after which spores werepatched out onto a fresh YPD plate and grown overnight at 30° C. Themating types of each spore from 8 four-spore tetrads were analyzed bycolony PCR. A single 4 spore tetrad with 2 MATA and 2 MATalpha sporeswas picked and stocked as strains Y1661 (MATA), Y1662 (MATA), Y1663(MATalpha), and Y1664 (MATalpha).

Host strain 1515 was generated by transforming strain Y1664 with plasmidTOPO-Phase I digested to completion using PmeI restriction endonuclease.Host cell transformants were selected on YPD medium containing 300 ug/mLhygromycin B.

Host strain 1762 was generated by transforming strain Y1515 with plasmidTOPO-Phase II digested to completion using PmeI restrictionendonuclease. Host cell transformants were selected on YPD mediumcontaining 100 ug/mL nourseothricin.

Host strain 1770 was generated by transforming strain Y1762 in two stepswith expression plasmid pAM404 and plasmid TOPO-Phase III digested tocompletion using PmeI restriction endonuclease. Expression plasmidpAM404 was derived from plasmid pAM353, which was generated by insertinga nucleotide sequence encoding a β-farnesene synthase into thepRS425-Gal1 vector (Mumberg et. al. (1994) Nucl. Acids. Res. 22(25):5767-5768). The nucleotide sequence insert was generated synthetically,using as a template the coding sequence of the β-farnesene synthase geneof Artemisia annua (GenBank accession number AY835398) codon-optimizedfor expression in Saccharomyces cerevisiae (SEQ ID NO: 121). Thesynthetically generated nucleotide sequence was flanked by 5′ BamHI and3′ XhoI restriction sites, and could thus be cloned into compatiblerestriction sites of a cloning vector such as a standard pUC or pACYCorigin vector. The synthetically generated nucleotide sequence wasisolated by digesting to completion the DNA synthesis construct usingBamHI and XhoI restriction enzymes. The reaction mixture was resolved bygel electrophoresis, the approximately 1.7 kb DNA fragment comprisingthe β-farnesene synthase coding sequence was gel extracted, and theisolated DNA fragment was ligated into the BamHI XhoI restriction siteof the pRS425-Gal1 vector, yielding expression plasmid pAM353. Thenucleotide sequence encoding the β-farnesene synthase was PCR amplifiedfrom pAM353 using primers GW-52-84 pAM326 BamHI (SEQ ID NO: 188) andGW-52-84 pAM326 NheI (SEQ ID NO: 189). The resulting PCR product wasdigested to completion using BamHI and NheI restriction enzymes, thereaction mixture was resolved by gel electrophoresis, the approximately1.7 kb DNA fragment comprising the β-farnesene synthase coding sequencewas gel extracted, and the isolated DNA fragment was ligated into theBamHI NheI restriction site of vector pAM178 (SEQ ID NO: 122), yieldingexpression plasmid pAM404. Host cell transformants with pAM404 wereselected on Complete Synthetic Medium (CSM) lacking methionine andleucine. Host cell transformants with pAM404 and Phase III completeassembled polynucleotide were selected on CSM lacking methionine andleucine and containing 200 ug/mL G418.

Host strain 1793 was generated by transforming strain Y1770 with a URA3knockout construct (SEQ ID NO: 123). The knockout construct wasgenerated by first generating DNA fragments URA3US (generated fromSaccharomyces cerevisiae strain CEN.PK2 genomic DNA using PCR primersKMH33-276-21-URA3 5′.fwd (SEQ ID NO: 147) and KMH34-276-21-URA3 5′.rev(SEQ ID NO: 148)) and URA3DS (generated from Saccharomyces cerevisiaestrain CEN.PK2 genomic DNA using PCR primers KMH35-276-21-URA3 3′.fwd(SEQ ID NO: 149) and KMH36-276-21-URA3 3′.rev (SEQ ID NO: 150); followedby stitching the two DNA fragments together using PCR primersKMH33-276-21-URA3 5′.fwd and KMH36-276-21-URA3 3′.rev. Host celltransformants were selected on YPD medium containing 5-FOA.

Host strain YAAA was generated by transforming strain Y1793 with thePhase I marker recycling assembled polynucleotide (see Table 7). Hostcell transformants were selected on CSM lacking methionine and uracil.The URA3 marker was excised by growing the cells overnight in YPD mediumat 30° C. on a rotary shaker at 200 rpm, and then plating the cells ontoagar containing 5-FOA. Marker excision was confirmed by colony PCR.

Host strain YBBB was generated by transforming strain YAAA with thePhase II marker recycling assembled polynucleotide (see Table 7). Hostcell transformants were selected on CSM lacking methionine and uracil.The URA3 marker was excised by growing the cells overnight in YPD mediumat 30° C. on a rotary shaker at 200 rpm, and then plating the cells ontoagar containing 5-FOA. Marker excision was confirmed by colony PCR.

Host strain Y1912 was generated by transforming strain YBBB with thePhase III marker recycling assembled polynucleotide (see Table 7). Hostcell transformants were selected on CSM lacking methionine and uracil.The URA3 marker was excised by growing the cells overnight in YPD mediumat 30° C. on a rotary shaker at 200 rpm, and then plating the cells ontoagar containing 5-FOA. Marker excision was confirmed by colony PCR.

Host strain Y1913 was generated by transforming strain Y1912 with theSTE5 knockout assembled polynucleotide (see Table 7). Host celltransformants were selected on CSM lacking methionine and uracil.

Host strain Y1915 was generated from strain Y1913 by curing the strainfrom pAM404 and transforming the resulting strain with the IME1 knockoutassembled polynucleotide (see Table 7). Strain Y1913 was propagated innon-selective YPD medium at 30° C. on a rotary shaker at 200 rpm.Approximately 100 cells were plated onto YPD solid media and allowed togrow for 3 days at 30° C. before they were replica-plated no CSM plateslacking methionine and leucine where they were grown for another 3 daysat 30° C. Cured cells were identified by their ability to grow onminimal medium containing leucine and their inability to grow on mediumlacking leucine. A single such colony was picked and transformed withthe IME1 knockout assembled polynucleotide. Host cell transformants wereselected on CSM lacking methionine and uracil.

Example 9

This example describes methods for selecting annealable linker sequencesto be used to assemble component polynucleotides encoding a promoter anda protein coding sequence into a assembled polynucleotide by theinventive methods disclosed herein.

MULEs encoding promoters followed by two different candidate annealablelinker sequences, annealable linker sequence RYSE 15 (R15; SEQ ID NO:15) and annealable linker sequence RYSE 7 (R7; SEQ ID NO: 7), as well asMULEs encoding GFP preceded by the two annealable linker sequences, werePCR amplified as described in Table 8.

TABLE 8 Amplified MULEs Encoding Promoters and GFP with AnnealableLinker Sequences RYSE 15 (R15) or Annealable Linker Sequence RYSE 7 (R7)Size MULE Type* Primers (bp) Template pGAL1-R15 P Plan X19 (SEQ ID NO:236) 698 S. cerevisiae strain CEN.PK2 Plan X20 (SEQ ID NO: 237) genomicDNA pTDH3-R15 P Plan X47 (SEQ ID NO: 238) 613 S. cerevisiae strainCEN.PK2 Plan X48 (SEQ ID NO: 239) genomic DNA pCYC1-R15 P Plan X11 (SEQID NO: 240) 645 S. cerevisiae strain CEN.PK2 Plan X12 (SEQ ID NO: 241)genomic DNA pGAL1-R7 P Plan X19 (SEQ ID NO: 236) 692 S. cerevisiaestrain CEN.PK2 Plan X64 (SEQ ID NO: 242) genomic DNA pTDH3-R7 P Plan X47(SEQ ID NO: 238) 607 S. cerevisiae strain CEN.PK2 Plan X71 (SEQ ID NO:243) genomic DNA pCYC1-R7 P Plan X11 (SEQ ID NO: 240) 639 S. cerevisiaestrain CEN.PK2 Plan X78 (SEQ ID NO: 244) genomic DNA R7-GFP GsT Plan X96(SEQ ID NO: 247) 1378 RABit 634 plasmid DNA** Plan X88 (SEQ ID NO: 245)A-GFP GsT Plan X89 (SEQ ID NO: 246) 1385 RABit 634 plasmid DNA** PlanX88 (SEQ ID NO: 245) PCR reactions contained: 67 uL ddH2O, 20 uL 5x HFBuffer, 2 uL of each Primer (10 uM), 1 uL dNTP mix (200 uM), 1 uLPhusion DNA Polymerase (New England Biolabs, Ipswich, MA), and 9 uL Y002genomic DNA or RABit 634 plasmid DNA. PCR amplification was performed asfollows: 1 cycle of denature at 98° C. for 2 minutes; 9 cycles ofdenature at 98° C. for 15 seconds, anneal at 61° C. for 30 secondsdecreasing by 1° C. each cycle, and extend at 72° C. for 1 minute; 26rounds of denature at 98° C. for 15 seconds, anneal at 52° C. for 30seconds, and extend at 72° C. for 1 minute; 1 cycle of final extend at72° C. for 7 minutes; and a final hold at 4° C. *G = gene; s = stopcodon; T = terminator; P = promoter. **RABit 634 comprises the codingsequence of the green fluourescent protein (GFP) followed by theterminator of the ADH1 gene of Saccharomyces cerevisiae.The PCR reactions were resolved by gel electrophoresis, the MULEs weregel purified, and the purified MULEs were used to assemble testassembled polynucleotides. To this end, MULEs and assembly vectors (seeTable 6) to be assembled (see Table 9) were placed together in a tube(333 fmole of each assembly vector, 667 fmole for each MULE) anddigested using LguI restriction enzyme (Fermentas, Glen Burnie, Md.).The restriction enzyme was heat inactivated for 20 minutes at 65° C. Thesamples were split into three 30 uL reactions; water, buffer, dNTPs, andDNA polymerase were added to each reaction mixture, and a first round ofPCR amplification was initiated. Terminal primers were then added to thereaction mixtures, and a second round of PCR amplification was performed(see Table 9). The three PCR reaction mixtures were combined in onetube, the reaction mixtures were resolved by gel electrophoresis, andthe PCR products were gel purified.

TABLE 9 Terminal Primers for Assembly of Test Assembled polynucleotidesMULEs (see Table 8) and Assembled Assembly Vectors (see Tablepolynucleotide Terminal Terminal Assembly 6) To Be Combined* Size (kb)Primer 1 Primer 2 1 97_555_pGAL1-A_A-GFP_24 4.7 S000 S019 297_555_pTDH3-A_A-GFP_24 4.6 (SEQ ID (SEQ ID NO: 397_555_pCYC1-A_A-GFP_24 4.7 NO: 45) 64) 7 97_555_pGAL1-R7_R7-GFP_24 4.78 97_555_pTDH3-R7_R7-GFP_24 4.6 9 97_555_pCYC1-R7_R7-GFP_24 4.6 PCRreactions contained: 41 uL ddH2O, 20 uL 5x HF Buffer, 5 uL of eachterminal primer (1 uM), 2 uL dNTP mix (200 uM), 1.8 uL Phusion DNAPolymerase, and 30 uL MULE or LguI digested assembly vector. The firstround of PCR amplification was performed as follows: 1 cycle of denatureat 98° C. for 2 minutes; 5 cycles of denature at 98° C. for 30 seconds,anneal at 60° C. for 30 seconds, and extend at 72° C. for 2.5 minutes;followed by a hold at 4° C. for addition of the two terminal primers.The second round of PCR amplification was performed as follows: 1 cycleof denature at 98° C. for 2 minutes; 35 rounds of denature at 98° C. for12 seconds, anneal at 60° C. for 30 seconds, and extend at 72° C. for2.5 minutes; 1 cycle of final extend at 72° C. for 7 minutes; and afinal hold at 4° C. *Assembly vectors are designated with numbers, andMULEs with names.The test assembled polynucleotides were used to transform aSaccharomyces cerevisiae host strain that was URA3 deficient and had adeletion of the GAL80 locus. Host cell transformants were selected onCSM lacking uracil, and correct genomic integration of the assembledpolynucleotide was confirmed by colony PCR. Two verified colonies fromeach transformation were picked into 360 uL Bird Seed Medium (BSM)containing 2% sucrose, and the cultures were incubated for 48 hours at30° C. on a rotary shaker at 999 rpm. An aliquot of 14.4 uL was takenfrom each well and transferred to 1.1 mL BSM containing 4% sucrose on a96-well block plate, and cultured for another 6 hours at 30° C. on arotary shaker at 999 rpm, at which point 100 uL of each culture wastransferred to a well of a clear bottom 96-well plate for analysis ofGFP expression. GFP expression in each well was analyzed by measuring515 nm emission after 485 nm excitation on an M5 Plate readerspectrophotometer (Molecular Devices, Sunnyvale, Calif.). Measured GFPconcentrations were normalized for cell culture growth by dividing bythe OD600 reading for each culture.As shown in Table 10, annealable linker sequence RYSE 15 enabledincreased GAL1, TDH3, and CYC1 promoter driven expression of the GFPreporter gene in the test assembled polynucleotides compared toannealable linker sequence RYSE 7.

TABLE 10 GFP Expression in Host Cells Harboring Test Assembledpolynucleotides Comprising Either Annealable Linker Sequence RYSE 15(R15) or Annealable Linker Sequence RYSE 7 (R7) Between Promoter and GFPReporter Annealable linker sequence Average % GFP positioned expression(compared to between average % GFP expression promoter obtained withhost cells harboring and GFP one of 3 seamless control constructs*;reporter gene in average for 2 independent host cell isolates) testassembled GAL1 TDH3 CYC1 Average across all polynucleotide promoterpromoter promoter three promoters R15 79.34 91.42 81.92 84.22 R7 27.4354.68 46.31 42.81 *The seamless control constructs had an identicalstructure as the test assembled polynucleotides except that the promotersequences were seamlessly linked to the GFP reporter gene (i.e., withoutan intervening annealable linker sequence).

Example 10

This example describes methods for the high-throughput combinatorialassembly of polynucleotides, and methods for the high-throughputgeneration of host cells comprising combinatorially combinedpolynucleotides.

The component polynucleotides used in this example, and the expectedassembled and combined polynucleotides generated from these componentpolynucleotides, are schematically illustrated in FIG. 12A. Thecomponent polynucleotides comprised DNA segments encoding an upstreamand a downstream chromosomal targeting sequence (US and DS), 6 differentpromoters (P), 35 different proteins (G), and a 5′ and a 3′ segment ofthe URA3 selectable marker (URA and RA3, respectively), flanked byannealable linker sequences pairs or primer binding segment/annealablelinker sequence pairs.

Component polynucleotides were released from assembly vectors bydigesting RABits or MULES using LguI restriction endonuclease. To thisend, 96-well plates (“LguI Digestion Plates”) were set up as shown inthe table below, and the plates were incubated at 37° C. for 75 min,after which the LguI restriction endonuclease was heat inactivated at65° C. for 20 min in a PCR machine.

LguI Digestion Plates Component (per well) Volume (uL) 667 fMoles RABitor MULE Variable 10x Tango Buffer (Fermentas, 10   Glen Burnie, MD) LguI(Fermentas, Glen Burnie, 2.5 MD) ddH2O to 100

Component polynucleotides were assembled by SOE. For each LguI DigestionPlate, triplicate 96-well plates (“SOE/PCR Plates”) were set up andthermocycled in a PCR machine as shown in the table below.

SOE/PCR Plates Component (per well) Volume (uL) ddH2O 41 5x Phusion HFBuffer 20 (New England Biolabs, Ipswich, MA) 10 mM dNTP mix  2 PhusionDNA polymerase   1.8 (New England Biolabs, Ipswich, MA) 30 LguI-digestedRABits or MULEs to be assembled

30 Total: 95 Thermocycling conditions Initial Denature 98° C.  2 min 7cycles Denature 98° C. 30 sec Anneal 67° C. 30 sec Extend 72° C.  5 minHold  4° C. ∞

Assembled polynucleotides were PCR amplified. Each SOE/PCR Platereceived additional reagent and was thermocycled in a PCR machine asshown in the table below. Corresponding wells on SOE/PCR plates werepooled into 96-deep well blocks, and assembled polynucleotides werepurified using the Omega Biotek E-Z 96® Cycle-Pure Kit (Omega Bio-TekInc., Norcross, Ga.) as per manufacturer's suggested protocol(approximate end-volumes of 45 uL).

SOE/PCR Plates Additional Component (per well) Volume (uL) 10 mM stockof terminal primers S000 (SEQ ID 10 NO: 45) and S019 (SEQ ID NO: 64)Thermocycling conditions Initial Denature 98° C.   2 min 35 cyclesDenature 98° C.  12 sec Anneal 67° C.  30 sec Extend 72° C. 4.5 minFinal Extend 72° C.   7 min Hold  4° C. ∞

FIG. 12B shows exemplary assembled polynucleotides (boxed) resolved on a1% agarose gel.

Purified assembled polynucleotides were digested with LguI restrictionendonuclease to generate sticky ends for cloning. To this end, 96-wellplates (“LguI Assembled Polynucleotide Digestion Plates”) were set up asshown in the table below, and the plates were incubated at 37° C. for 60min, after which the LguI restriction endonuclease was heat inactivatedat 65° C. for 20 min in a PCR machine. LguI digested assembledpolynucleotides were gel purified using the ZR-96 Zymoclean™ Gel DNARecovery Kit (Zymo Research Corporation, Orange, Calif.) as permanufacturer's recommended protocol.

LguI Assembled Polynucleotide LguI Digestion Plates Component (per well)Volume (uL) Purified assembled polynucleotide 43 10x Tango Buffer 5 LguI2

Assembled polynucleotides were ligated into a pUC-19 based vectorbackbone. When no insert is ligated into this vector, a pTRC promoter(i.e., promoter of the TRC gene of Saccharomyces cerevisiae) drivesexpression of GluRS and kills the host cell. 96-well plates (“LigationPlates”) were set up as shown in the table below, and the plates wereincubated at 24° C. for 15 min, and then at 16° C. overnight. Ligationproducts were purified using the ZR-96 DNA Clean & Concentrator™-5 (ZymoResearch Corporation, Orange, Calif.) as per manufacturer's suggestedprotocol.

Ligation Plates Component (per well) Volume (uL) ddH2O 5 10x T4 DNALigase Buffer 2 Vector backbone 2 Purified assembled polynucleotide 10T4 DNA ligase (NEB, Ipswich, MA) 1

Ligation products were electroporated into E. coli competent cells.Pre-chilled 96-well electroporation plates were set up andelectroporations were carried out as shown in the table below.

Electroporation Plates Component (per well) Volume (uL) Purifiedligation products 10 Lucigen 10G competent cells (Lucigen 25Corporation, Middleton, WI) Electroporation settings 2400 V 750 Ω 25 uF

1.1 mL 96-well culture plates (“Culture Plates”) containing 250 uL ofpre-warmed SOC were set up, and 100 uL SOC was taken from each well andadded to the electroporated cells immediately after electroporation. TheSOC and cells were mixed, and 100 uL of each mixture was transferredback to the Culture Plates. The Culture Plates were incubated at 37° C.for 1 hour in a Multitron II Incubator Shaker (ATR Biotech, Laurel,Md.). Two dilutions of cells (3 ul and 240 ul) were plated on LB agarcomprising 50 ug/mL kanamycin, and incubated overnight at 37° C.Colonies were picked and grown in 96 deep well plates comprising 1 mL LBmedium with kanamycin per well, and DNA was extracted for restrictionanalysis using LguI restriction endonuclease. Results of suchrestriction analysis for 22 of 24 exemplary colonies comprising anapproximately 8 kb combined polynucleotide are shown in FIG. 12C.

Yeast cells comprising chromosomally integrated combined polynucleotideswere generated by host cell mediated homologous recombination betweenterminal chromosomal targeting sequences and selectable marker segmentsof the assembled polynucleotides. To this end, 96-well PCR plates(“Yeast Transformation Plates”) were set up and heat shocktransformations were carried out in a PCR machine as shown in the tablebelow.

Yeast Transformation Plates Component (per well) Volume (uL) MiniprepDNA (20 ng/uL) 10 Competent yeast cells* 40 PEG/SS/LiAc master mix** 200Heat shock 30° C. 30 min 42° C. 45 min 24° C. (optional) 30 min*Prepared by growing cells in 100 mL YPD overnight, diluting the cultureand growing to an OD600 of about 0.8 overnight, spinning the cultures at3,000 g for 5 min, washing the cell pellet with 1 L ddH2O, washing thecell pellet with 1 L 100 mM lithium acetate (LiAc), and resuspending thecell pellet to a total volume of 18 mL in 100 mM LiAc. **Master mixsufficient for 4 PCR plates contains 100 mL 50% PEG, 4 mL boiled (95° C.for at least 10 min) single-stranded DNA, 15 mL 1M LiAc.

The Yeast Transformation Plates were spun at 2,000 g for 2 min,supernatants were removed, and cell pellets were washed three times with200 uL ddH2O. Cell pellets were resuspended with 100 uL cold Bird SeedMedia (BSM) taken from previously prepared pre-chilled 96-well cultureplates (“Seed Plates”) containing 360 uL cold BSM per well. Thesuspended cells were transferred to the Seed Plates, and were grownovernight at 30° C. in a Multitron II Incubator Shaker. The Seed Plateswere spun at 3,000 g for 5 min, all but 60 uL of the liquid was removed,and covered Seed Plates were shaken at 1,000 rpm to resuspend the cellpellets.

Example 11

This example describes methods for generating yeast cells comprisingassembled polynucleotides generated by host cell mediated homologousrecombination.

The assembled polynucleotide and component polynucleotides used in thisexample, and the expected chromosomal locus obtained upon assembly andchromosomal integration, are schematically illustrated in FIG. 13A.

Yeast cell transformations were carried out as described in the tablebelow. Following heat shock, the cells were spun down, supernatant wasremoved, cells were resuspended in 400 uL ddH2O, and host celltransformants were selected for by plating 100-200 uL of the cellsuspension on agar lacking uracil.

Yeast Transformation Component Volume (uL) Component and assembledpolynucleotides (300-500 ng 20 each) Competent yeast cells* cell pellet*50% PEG solution 240  1 M LiAc pH 8.4-8.9 36 Boiled (95° C. for 5 min)single-stranded DNA (10 mg/mL) 10 (Invitrogen, Carlsbad, CA) ddH2O 54Heat shock 42° C. 40 min *Prepared by growing cells from a colony in 25mL YPD overnight at 30° C. to an OD600 of 0.7-0.9, spinning down thecells, washing the cell pellet with 5-10 mL ddH2O, washing the cellpellet with 1 mL ddH2O, washing the cell pellet with 1 mL 100 mM lithiumacetate (LiAc), spinning in microcentrifuge for 30 sec to pellet thecells, and discarding the supernatant.

Successful integration of assembled polynucleotides was determined bycPCR using cPCR primers A, B, E, and F (5′ junction of chromosomalintegration site) or cPCR primers C, D, G, and H (3′ junction ofchromosomal integration site) (FIG. 13A). As shown in FIG. 13B, all 8colonies analyzed produced the 700 bp PCR band indicative of a positivechromosomal integration event of the expected assembled polynucleotideand lacked the 950 bp PCR band that the native locus would haveproduced.

Example 12

This example describes methods for the high-throughput generation ofyeast cells comprising combinatorially assembled and combinatoriallycombined polynucleotides generated by host cell mediated homologousrecombination.

The component polynucleotides used in this example, and the expectedcombined polynucleotides obtained upon assembly and combination by hostcell mediated homologous recombination, are schematically illustrated inFIG. 14A. The component polynucleotides comprised DNA segments encodingan upstream and a downstream chromosomal targeting sequence (US and DS),6 different promoters (P), 35 different proteins (G), and a 5′ and a 3′segment of the URA3 selectable marker (URA and RA3, respectively),flanked by annealable linker sequences pairs or primer bindingsegment/annealable linker sequence pairs.

Component polynucleotides were released from assembly vectors bydigesting RABits or MULES using LguI restriction endonuclease. To thisend, 96-well plates (“LguI Digestion Plates”) were set up as shown inthe table below, and the plates were incubated at 37° C. for 75 min,after which the LguI restriction endonuclease was heat inactivated at65° C. for 20 min in a PCR machine.

LguI Digestion Plates Component (per well) Volume (uL) 667 fMoles RABitor MULE Variable 10x Tango Buffer (Fermentas, 5   Glen Burnie, MD) LguI(Fermentas, Glen Burnie, 2.5 MD) ddH2O to 50

To generate yeast cells comprising chromosomally integratedcombinatorially assembled and combinatorially combined polynucleotides96-well PCR plates (“Yeast Transformation Plates”) were set up and heatshock transformations were carried out in a PCR machine as shown in thetable below.

Yeast Transformation Plates Component (per well) Volume (uL) Componentpolynucleotides 10 Competent yeast cells* 40 PEG/SS/LiAc master mix**200 Heat shock 30° C. 30 min 42° C. 45 min 24° C. (optional) 30 min*Prepared by growing cells in 100 mL YPD overnight, diluting the cultureand growing to an OD600 of about 0.8 overnight, spinning the cultures at3,000 g for 5 min, washing the cell pellet with 1 L ddH2O, washing thecell pellet with 1 L 100 mM lithium acetate (LiAc), and resuspending thecell pellet to a total volume of 18 mL in 10 mM LiAc. **Master mixsufficient for 4 PCR plates contains 100 mL 50% PEG, 4 mL boiled (95° C.for at least 10 min) single-stranded DNA, 15 mL 1M LiAc.

The Yeast Transformation Plates were spun at 2,000 g for 2 min,supernatants were removed, and cell pellets were washed three times with200 uL ddH2O. Cell pellets were resuspended with 100 uL cold Bird SeedMedia (BSM) taken from previously prepared pre-chilled 96-well cultureplates (“Seed Plates”) containing 360 uL cold BSM per well. Thesuspended cells were transferred to the Seed Plates, and were grownovernight at 30° C. in a Multitron II Incubator Shaker. The Seed Plateswere spun at 3,000 g for 5 min, all but 60 uL of the liquid was removed,and covered Seed Plates were shaken at 1,000 rpm to resuspend the cellpellets. Various dilutions of cells were plated on agar lacking uracil,and incubated overnight at 37° C. Colonies of yeast cell transformantsharboring a functional URA3 selectable marker were picked and analyzed.

All publications, patents and patent applications cited in thisspecification are herein incorporated by reference as if each individualpublication or patent application were specifically and individuallyindicated to be incorporated by reference. Although the foregoinginvention has been described in some detail by way of illustration andexample for purposes of clarity of understanding, it will be readilyapparent to those of ordinary skill in the art in light of the teachingsof this invention that certain changes and modifications can be madethereto without departing from the spirit or scope of the appendedclaims. The embodiments of the present invention described above areintended to be merely exemplary, and those skilled in the art willrecognize, or be able to ascertain using no more than routineexperimentation, numerous equivalents to the specific proceduresdescribed herein. All such equivalents are considered to be within thescope of the present invention and are covered by the following claims.Furthermore, as used in this specification and claims, the singularforms “a,” “an” and “the” include plural forms unless the contentclearly dictates otherwise.

1. A composition comprising: (a) one or more first nucleic acidmolecules, wherein each first nucleic acid molecule is circular andcomprises, in a 5′ to 3′ orientation, a first restriction site RA₀, anyDNA segment selected from the group D₀, an annealable linker sequenceLB₀, and a second restriction site RB₀; (b) one or more intermediatenucleic acid molecules, wherein each intermediate nucleic acid moleculen is circular and comprises, in a 5′ to 3′ orientation, a firstrestriction site RA_(n), a first annealable linker sequence LA_(n), anyDNA segment selected from the group D_(n), a second annealable linkersequence LB_(n), and a second restriction site RB_(n), and wherein nrepresents an integer from one to the number of intermediate nucleicacid molecules; and (c) one or more last nucleic acid molecules, whereineach last nucleic acid molecule is circular and comprises, in a 5′ to 3′orientation, a first restriction site RA_(m), an annealable linkersequence LA_(m), any DNA segment selected from the group D_(m), a secondrestriction site RB_(m), wherein m represents an integer one greaterthan the number of intermediate nucleic acid molecules; wherein each ofrestriction sites RA₀ through RB_(m) is independently cleavable by oneor more Type IIS restriction endonucleases, wherein each of restrictionsites RA₀ through RB_(m) is oriented so that cleavage of each of saidrestriction sites RA₀ through RB_(m) separates their recognition andcleavage sites from the resulting respective nucleic acid molecule thatcomprises D₀ and LB₀; LA_(n), D_(n), and LB_(n); or LA_(m) and D_(m);whereupon cleavage of restriction sites RA₀ through RB_(m) anddenaturation of the resulting linear nucleic acid molecules, eachannealable linker sequence LB_((p-1)) is capable of hybridizing to thecomplement of annealable linker sequence LA_(p), wherein n is an integerthat varies from 1 to (m−1), wherein p represents an integer from 1 tom, and wherein each group D₀, . . . D_(n), . . . D_(m) independentlyconsists of one or more DNA segments.
 2. The composition of claim 1,wherein each of said one or more first nucleic acid molecules furthercomprises any primer binding segment selected from the group PApositioned 5′ to the DNA segment selected from the group D₀, whereineach of said one or more last nucleic acid molecules further comprisesany primer binding segment selected from the group PB positioned 3′ tothe DNA segment selected from the group D_(m).
 3. The composition ofclaim 1, wherein upon cleavage of restriction sites RA₀ through RB_(m)and denaturation of the resulting linear nucleic acid molecules, eachannealable linker sequence LB_((p-1)) is capable of selectivelyhybridizing to the complement of annealable linker sequence LA_(p)compared to the other annealable linker sequences, or their complements,in the composition.
 4. The composition of claim 1, wherein therestrictions sites RA₀ through RB_(m) are cleavable by SapI or LguIrestriction endonuclease.
 5. The composition of claim 1, wherein two ormore annealable linker sequences are at least 24 nucleotides in lengthand have a melting temperature of at least 60° C.
 6. A compositioncomprising a plurality of linear nucleic acid molecules formed bydigesting the composition of claim 1 with one or more Type IISrestriction endonucleases capable of cleaving the restriction sites RA₀through RB_(m).
 7. A method of generating an assembled polynucleotidefrom a plurality of component polynucleotides comprising the steps of:(a) digesting an assembly composition with one or more Type IISrestriction endonucleases to generate a components composition, theassembly composition comprising: (i) one or more first nucleic acidmolecules, wherein each first nucleic acid molecule is circular andcomprises, in a 5′ to 3′ orientation, a first restriction site RA₀, anyprimer binding segment selected from the group PA, any DNA segmentselected from the group D₀, an annealable linker sequence LB₀, and asecond restriction site RB₀; (ii) one or more intermediate nucleic acidmolecules, wherein each intermediate nucleic acid molecule n is circularand comprises, in a 5′ to 3′ orientation, a first restriction siteRA_(n), a first annealable linker sequence LA_(n), any DNA segmentselected from the group D_(n), a second annealable linker sequenceLB_(n), and a second restriction site RB_(n), and wherein n representsan integer from one to the number of intermediate nucleic acidmolecules; and (iii) one or more last nucleic acid molecules, whereineach last nucleic acid molecule is circular and comprises, in a 5′ to 3′orientation, a first restriction site RA_(m), an annealable linkersequence LA_(m), any DNA segment selected from the group Dm, any primerbinding segment selected from the group PB, a second restriction siteRB_(m) wherein m represents an integer one greater than the number ofintermediate nucleic acid molecules; wherein each of restriction sitesRA₀ through RB_(m) is independently cleavable by the one or more Type HSrestriction endonucleases, wherein each of restriction sites RA₀ throughRB_(m) is oriented so that cleavage of each of said restriction sitesRA₀ through RB_(m) separates their recognition and cleavage sites fromthe resulting respective nucleic acid molecule that comprises D₀ andLB₀; LA_(n), D_(n), and LB_(n); or LA_(m) and D_(m); whereupon cleavageof restriction sites RA₀ through RB_(m) and denaturation of theresulting linear nucleic acid molecules, each annealable linker sequenceLB_((p-1)) is capable of hybridizing to the complement of annealablelinker sequence LA_(p), wherein n is an integer that varies from 1 to(m−1), wherein p represents an integer from 1 to m, and wherein eachgroup D₀, . . . D_(n), . . . and D_(m) consists of one or more DNAsegments; and (b) contacting the components composition with DNApolymerase, deoxyribonucleoside triphosphates and one or more firstprimers and one or more second primers, under conditions suitable fordenaturation of the nucleic acid molecules, annealing of annealablelinker sequence LB_((p-1)) to annealable linker sequence LA_(p), andextension therefrom; wherein each said first primer is capable ofhybridizing to one of said primer binding segments selected from thegroup PA and each said second primer is capable of hybridizing to one ofsaid primer binding segments selected from the group PB; and subjectingthe components composition to polymerase chain reaction, wherein apolynucleotide is assembled which comprises, in a 5′ to 3′ orientation,one DNA segment selected from each of the groups D₀, . . . D_(n) . . .and D_(m).
 8. The method of claim 7, wherein two or more annealablelinker sequences are at least 24 nucleotides in length and have amelting temperature of at least 60° C.
 9. The method of claim 7, whereineach annealable linker sequence LB_((p-1)) is identical in sequence toannealable linker sequence LA_(p).
 10. The method of claim 7, whereinthe restriction sites RA₀ through RB_(m) are cleavable by the same TypeIIS restriction endonuclease.
 11. The method of claim 7, wherein therestrictions sites RA₀ through RB_(m) are cleavable by SapI or LguIrestriction endonuclease, and the Type IIS restriction endonuclease ofstep (a) is SapI or LguI.
 12. A method of generating a host cellcomprising a polynucleotide, the method comprising the steps of: (a)transforming a host cell with a polynucleotide assembled according toclaim 7; and (b) selecting a host cell comprising the assembledpolynucleotide.
 13. The method of claim 12, wherein the assembledpolynucleotide comprises a selectable marker and step (b) comprisespropagating the transformed host cell on selectable media.
 14. Themethod of claim 12, further comprising transforming the host cell with alinearized plasmid comprising: (i) a first region of homology withprimer binding segment PA; and (ii) a second region of homology withprimer binding segment PB, wherein said first and second regions ofhomology are of sufficient length to initiate host cell mediatedhomologous recombination between said polynucleotide and said plasmid toform a circularized plasmid in the host cell.
 15. A method of generatinga host cell comprising a polynucleotide, the method comprising the stepsof: (a) transforming a host cell with the composition of claim 6,wherein each annealable linker sequence LB_((p-1)) comprises a region ofhomology with annealable linker sequence LA_(p) of sufficient length toinitiate host cell mediated homologous recombination between LB_((p-1))and LA_(p) wherein p represents an integer from 1 to m, wherein saidhomologous recombination results in the assembly of a polynucleotide;and (b) selecting a host cell comprising an assembled polynucleotide,wherein the assembled polynucleotide comprises in a 5′ to 3′orientation, one DNA segment selected from each of the groups D₀, . . .D_(n), . . . and D_(m).
 16. The method of claim 15, wherein (a) each ofthe one or more first linear nucleic acid molecules further comprises afirst region of homology with a first integration site of the host cellgenome; and (b) each of the one or more last linear nucleic acidmolecules further comprises a second region of homology with a secondintegration site of the host cell genome, wherein said first and secondregions of homology are of sufficient length to initiate host cellmediated homologous recombination with said first and second integrationsites, respectively, wherein said homologous recombination results inintegration of an assembled polynucleotide into the host cell genome.17. The method of claim 15, wherein at least one homologousrecombination of an annealable linker sequence LB_((p-1)) and LA_(p)forms a nucleic acid sequence that encodes a selectable marker gene. 18.The method of claim 15, further comprising transforming the host cellwith a linearized plasmid comprising: (i) a first region of homologywith the one or more first linear nucleic acid molecules; and (ii) asecond region of homology with the one or more last linear nucleic acidmolecules, wherein said first and second regions of homology are ofsufficient length to initiate host cell mediated homologousrecombination between an assembled polynucleotide and said plasmid toform a circularized plasmid in the host cell.